RE: Tectonic for isonic
I've been using Tectonics fins for over 8 years now, and I can side with Egor's view that they are arguably some of the best slalom fins around. The real questions are which model and what size would work the best for you. What general conditions and sail sizes are you considering in the match up?
I really like the Goldwings, and I've got the 34, 36 and 38cm sizes, but I find that the 34 has been my favorite of the bunch. However, I haven't been matching them up with an iSonic, so it's hard for me to say which size would best optimize the performance of iS101.
Really, I would think that Ian Fox can probably give you the best recommendation here. I'm sure that he has matched up most of the leading fins in the marketplace to the iSonics. It's my guess that he would recommend the 34 or 36, but that's just my take on the situation. Yet, if your thinking about sailing really max winds for the board, maybe the 32 would be in the mix too.