This is an issue that really bugs me.
Recently I ordered a few Techtonic fins and they all required serious sanding to fit into my F2 Missile XS, SX M & iSonic 87. Fortuneately the fins boxes seem the same throughout as all fins fit the same in the various boards.
In addition to this, the fin supplied with my F2 Missile XS required extensive sanding to fit the board it was supplied with!
Now I have to admit that the stock fin provided with the iSonic fitted perfectly and so this thread is aimed at F2 and Techtonics so really shouldn't be here but perhaps some users of this forum would comment if they have had the exact same problems.
Surely it can't be that hard for all fin and board manufacturers to tighten up in this area.