Confussion of a newbie STELLAR S18S

I have recently transitioned from a 26kg sit in touring kayak to a 13kg sot ski. I purchased the stellar s18s (excel build) and am very happy with its quality and comfort. I also changed my paddle from a flat blade to a wing paddle braca 4 and this is my first wing paddle. My original flat blade was 219 cm which I was using in the kayak but everybody recommended me to shorten my blade now that I'm in a ski and now my wing blade is adjustable from 210 to 215 cm. With my new ski I am sitting a lot higher above the water than what I used to in my kayak, now my new wing paddle feels way too short even if i set it at max 215cm. I have noticed that everybody is using a lot shorter of a paddle than me. Would this be because they are in different skis which perhaps seat the paddler lower to the water? 
The excel version of the s18s sits lightly on the water, also i only weigh 63kg so the entire boat does not sit in the water which i feel affets its tracking especially with side swells.
So what will clear up my confusion and know whether i need to lengthen my paddle or not are basically the following...

At my weight have i picked a too light of a ski?
Does the stellar s18s have a higher cog (seat) than most other skis thetefote requires a longer paddle?
Im 5 foot 9 inches, if you have paddled an s18s before does 210-215 sound about right to you?

When i use my flat 219 paddle my blade is fully submerged in the water, whereas when I use my new wing paddle at 210 or 215cm the blade is not fully submerged in the water, but people have told me this is due to my technique rather than the paddle being too short.

Thank you for reading and any advice knowledge or tips would be highly appreciated.
David

The length is pretty much the standard length for most paddlers, so you're fine with that. You will have to adjust your paddling style with the wing. Google proper technique on 'wing paddle' and you will see a totally different stroke. Basically you use your core to rotate and the blade takes an outward path and exits the water sooner than you may used to. Many videos online like Ivan Lawler for starters. Most of them show K1 sprint athletes that have pretty much perfect technique, but you will get the picture. It is not an easy thing to get right without a lot of paddle time...

Thanks for your input Jef. Yes i sure do need to get my technique right but i am very patient and confident that it will come together with constant practice and watching many many videos. So being a light paddler at 63kg do you think i made the wrong choice on getting the excel version which the bow does not sit in the water properly (pls see attached pics)

The paddle length sounds ok but you can cross check it at www.epickayaks.com/paddle-wizard

For comparison I am 5'6" and use 205-208 depending on conditions and my state. I started off with a 210-220 and while it felt ok at first as I was getting along with the stroke (still work in progress) it started to feel like a telephone pole so I got a shorter paddle.

It's most certainly technique. On the picture you posted I see that your water arm is bent quite a bit. Hard to go on by a single shot though. I recommend fitting a Gopro or a knock off camera on the boat for technique analysis and be ready to work on it a lot.
Stroke-wise, a wing is quite different from euro and a paddling a ski is quite different from a sea kayak.

This is my favorite learning video:

Every once in a while I rewatch it with a pen and paper and every time I find I either missed or misunderstood some things. It's quite a journey...

Thanks SpaceSputnik for confirming paddle length and as i mentioned previously that switching from a euro paddle  and a touring kayak for someone who only got their first boat in 2016 is a big leap and my technique needs alot of work and im sure ill enjoy the ride as i simply love my s18s,  had it for a month and prob been out every day the weather permits. My only concern now is whether im to light for the excel build of the s18s for it to perform well in swell and wind since the bow is not in the water fully. I love the acceleration of this ski, have already blitzed my top speed record from my last boat, but that did weigh 26kg. 
I really thought after reading many reviews that the weight of a paddler vs the constuction build and weight of the boat plays a role in how that boat will perform, putting aside the paddlers skills. Simply how well the boat sits in the water and how high the paddler sits surely plays a role in various aspects including tracking, wind resistance, paddle length, stability...etc

I think it's probably a little early in the game to question the boat. I would work on form for now and see where it takes you. Things change quite a bit as we progress.

David, if you are comfortable in the boat and it is stable enough for you to enjoy going out in a bit of wind and swell, then there is nothing wrong with the boat!  A heavier layup is only a couple kilo difference, so isn't going to significantly change the waterline.  If you were really curious you could fill a couple water bottles and throw them in front of the footboard in the well for some extra weight to see if it improves the experience in any way.  I recommend just focusing on the technique, as others here have mentioned.  

Your paddle is also fine.  Out of everyone in my training group, the guy running the longest paddle is around 212.  I go between 207-209 depending on conditions.  

Enjoy the journey!

David, you should be ok at the 210 setting. I run my paddle at 207ish...water is not static  so it's all a baseline. As far as the boat, you have an awesome craft. It will be good for any type of paddling you do. My friend had an older one, and out of all the different boats he had, that was his favorite. The Excel is a great choice, I doubt you will ever sell it so you will enjoy the lighter layup over time.

Little early? Ok thanks

Thank PSwitzer i am very comfortable in the boat on flat to choppy water but when i hit a bit of swell its not that im not comfortably its that the boat behaves differently than heavier boats i have had. When the swell hits me from the side its like the ski has no traction in the water. The bow lifts up and the nose of the ski kind of swings away in tje direction of the swell and slaps down on the water. 
Good idea about adding weight simply as a test rather than a permanent fixture, i have some 2kg sacks of sand ready to trial.
Before i purchased this ski i was doing some research and read how a few light weight paddles have shifted the seating position forward by 6 inches makes a big improvement but i cant find the article now rhat i need it, so ill try that as well. 

Good to know your friend is happy and thanks for your view about the excel version vs my weight. An experienced paddle who i was referred to told me the same thing, i never doubted him i just needed a second opinion before i make this boat truly mine and dive into it 100%. My other passion is building anf flying model aircraft, about 16 years ago i was advised by a well experienced pilot to do a build in a specific way, well that project was an expensive disaster as he ended up being wrong. So i have learnt it never hurts to get a second opinion and you guys have truly given me that. It only helps build trust in my original source.  Thanks jef and thanks for everyones input, i can now enjoy this boat and my technique at the same time

Looking at the pics, I am wondering a few things. It looks like you have a seat pad in your ski raising your center of gravity. Do you need a seat pad?  Do you need the back band too?  Separately, you mentioned skis swings in the direction of the wind etc. I guessing you are not applying constant equal pressure on the toe pedals thus allowing the boat to wander. You need to make sure the angle of the toe pedal is correct to achieve good leg drive with constant pressure on the toe pedals but with out over steering. Boat set up is key: toe pedal angle, leg length, setting the rudder straight, etc.  As someone else mentioned, paddle length needs to be 207-211. Shorter gives you more control and adds to your stability.  Hopefully you are using the 8 inch rudder vice the 4 inch at this point in your learning curve. Lastly, take a lesson from a reputable surfski instructor and your learning curve will be shorten dramatically.  Hope this helps.  Wesley, SurfskiRacing.com

Thanks so much for tapping in Wesley and a coincidence as well. Just last night i was reading some of your reviews and speed/stability tests of many boats including the s18s and it was there you wrote about different builds can perform differently. 
I have taken your advice about the above info which you also advised another paddler to check in another post. I have to say it feels like it has made a world of difference to me as far as feeling in connected to the boat and also increases the ease to rotate. I guess i set myself up as a touring kayak position. You are spot on about me not applying constant pressure to the foot peddles, i tend to not lock the upper part of my foot resulting in slack/lose rudder control and now that you mentioned it, it felt exactly like my rudder was flapping around. I can also see how pushing from the heels would help the bow of the boat in swell. It felt really good on dry land test this morning and cant wait to get on the water and practice. Yes i have a padded seat but its only about 5mm max, prob only elevates me 3mm by the time i sit on it. I was not well last year and lost 17kg and that hard plastic takes its toll on me after 30mins. A padded seat allows me to stay on the water for hours. The back rest is not in my way when im in a good posture, in fact it reminds me when i start to lean back. Its simply to rest back on every 20mins or so while i take a breather. Would this be an issue?
Yes i am still using the 8 inch understern rudder but since i paddle in shallow waters many of the times i have the smart track over stern rudder arriving tomorrow as im always worried about striking rocks. I imagine that the 8inch rudder would give more stability that an over stern one would?? So i should expect less stability with my over stern?
Lessons are definetly in the near future, if only they were  closer.
Your advice and tips have been very helpful. The way you explained the boats behaviour causes makes so much sense when i think back paddling under the rip bridge. Even though i was thrown around alot and was pretty scared, i never capsized
Thanks a million Wesley