RE: iSonic Questions
Per Roger's advice, mast track further back than center. Roger coaches to go almost all the way back, and if it tailwalks, keep moving it forward until it just stabilizes. That way you are riding off the fin the maximum possible. In my case I am just covering the larger entry rectangle with a Chinook single bolt base. I leave it in the same spot for 9.5 and 8.5 (mostly out of laziness, once I found a good spot, I stopped playing with it...).
Per your other question, above, you may eventually want to get a bigger fin (62-64 cm) for the 9.8 V8, but I doubt that is the reason you are having trouble getting planing consistently.