RE: bigger fin for EVO80
I've done fairly extensive tests with different fin sizes on all EVOs. On the 80, you can in fact use the Drake 26. As geo points out, for some people and in some conditions, it might make more sense to use the 23, but conversely, there are other sailors and other conditions where a 26 will help get the most from the board.
In short, what you will mainly get from the bigger fin is some more "effeciveness" with bigger sails, especially when you are underpowered. As geo points out (again) once at speed the bigger fin will not help as much. But one of the great things about the Drake Natual fins is that they are very versatile in the sense that at slower speeds a bigger version will still feel nice and loose and at higher speeds a smaller version will get more powerful. That measn that even for a goven board-sail-rider combination, there is quite a wide range of Naturals that will work and the best choice generally depend on riding/sailing speed.