Here you can find more informations about what I mean with Super Saiyan FP.
About the fact that transformations don't use RP, I am aware of that and I didn't mean reducing it with an item, though reducing it with the Super Saiyan skill maxed (in the case skill points for transformations would/will be available).
About the fact with the Kaio-Ken you're right, I don't know what to do: because SP would improve the skill stats (and even the CD as I was saying, that's where I am wrong) there isn't no solution with it, heh, I can't think of one.
Ah right Full-Powered Super Saiyan. Well even at 3 SP the Super Saiyan skill would still be the Super Saiyan skill. There would be no Full-Powered version. Even at 3 SP for a Turtle Hermit the drain would still be something to worried about because EP regen isn't very high in battle so the form would still go through EP mildly quickly, especially if you're spamming other skills.