finn for IS101 and 7,3sail

Hello I need some advise
I have an Isonic101 and sail it almost exclusivly with a 7,3 race rigg in 18-30knots of wind. I have two finns that i got with the board a drake 34 and 42. I have a feeling that the 34 is a bit to small although it feels pretty good wheras the 42 feels to big even in lighter winds. Would I gain a lot by bying a new finn and should it be 36 or 38, 38 is better spaced between my small and large finn but maybe 36 is the optimal size for speed with my sailsaize? Any comments on how the is101 feels with the 42finn and 7,0-7,5 sails and in what wind range do you use it? I am 1,95m and weigh 87kg by the way.

[Rave On]

I would suggest a 38 cm Vector Canefire

[nonopr]

I highly recommend Vector Fins Canefire in 38cm if you only have budget for one but a 40cm too if you have budget for it.
contact: VECTOR FINS [jeff@vectorfins.com]

Thanks for the help I, I will buy a 38cm fin then. Seem like a nice fit to my current finns.