Targets to upgrade?

Hi folks - looking for some advice on targets before thinking about a faster ski (perhaps a v12).

I'm in a v10s right now that I've been paddling for about a year. In that boat with current technique/fitness I'm around 11.5km/h over a 5k and 10.5-11 on 10k+ distances (fairly flat conditions). I've also started to paddle a trainer k1 (nelo viper 48) recently and approaching being comfortable/stable putting power down in that boat.

I'm looking for a good goal to set - e.g. what's a good pace level where thinking about a v12 would be reasonable?

Do you race and are you after the fastest possible boat to try to win?
Then moving to a faster boat is sensible. There is no 'pace' to determine this, but stability vs speed. A 'faster' hull is only faster if you stay upright and can consistently put down the power.

10.5 - 11kph is about where I was when racing, in a K1. Is it a fast speed?
I was reasonably pleased with it. Several clubmates would cruise at 12kph. A couple could sit on 12.5-13 for a couple of hours. 

If you are not racing, but after the thrill of speed downwind, I wouldn't bother going for a tippier boat. It will just limit the days when you can paddle.

Just to provide a different point of view... If you can get a V12 and get used to it in safe conditions while you keep the V10s for big days then by all means do it! It will make you a better paddler even if you keep the V10s for days where you're not fit for the V12 or prefer to have more safety margin, or prefer the familiar boat in a race.
If you can't keep the V10s then you need to get to the point where you feel totally comfortable in it and then time the upgrade so you don't have any races or big conditions for 3-4 months so you can get used to the V12 (or equiv).