I too use a 2009 v12.
Second question is easy - none of that stuff slows the boat down at all.
First question: The epic weedless is the best weedless rudder out there in my opinion. It is very balanced (shaft not at the lead edge), initiates turns the best (thanks to the steep section at the front) an in my experience is the most weedless.
The downside of the epic weedless is that is has to be used with the epic weedless weed guard (i make my own but to the same dimensions.) However, once you put the weedguard on (allow 5mm or less gap to the rudder) you will not be able to use the universal rudder that you own.
What you really need is to own both a weedles and a surf rudder from epic, because the both are compatable with the same weed guard. That way you can permanenly mount the weed guard to the ski with epoxy or some other suitable adhessive.
The self stick is NOT to fasten it to the ski. It is to hold the guard lightly on the ski while you try to find the right spot on the ski for it. Once found, trace the location with marker. Sand that spot on the hull, remove the adhesive from the guard base and sand that, and then use epoxy to glue it back in the outline.
As far as the weedless vs rough water weedles - i have only used the weedless. It is adequate up to 3 ft waves. Yhe rough water weedless will be better in waves, though I imagine it might have less bite than the universal rudder you already own. On my boat I use the weedless 95% of the time, the surf rudder the 5% of the time that I am going downwind, and I never used the universal rudder.
Current Skis: Nelo Vanquish AIR, Epic V10g4, NK 670 double, NK exrcize, Carbonology Feather, Think Jet, Knysna Sonic X
Former Skis: Epic v10g3, Kai Waa Vega, Epic V12 g2, Epic V12 g1, Epic v10 double, Nelo 550 g2, Fenn Elite S, Custom Kayaks Synergy