Sorry but the 500m record (for me) is set on a Carbon Art Speed 50 board.
I have not used the Isonic 105 in the latest competitions but I have tested:
Tectonics Goldwing 36
Very nice combination! A bit slippery but very fast when well tuned. I do not use the Drake 34 anymore. I use this fin in 12-18knots wind with 6,9 or 7,5 sail.
Tectonics Falcon F1 30
Very Fast!!!!!!!!!!! It surpriced me. I really like the combination. I have only used it once and I hitted a peak speed of 40 knots. Long distance was no option on that surfspot. I would use this fin from 16-30knots wind with 6.3 or 5.7 sail
There is a video for some impression ( o2bnme you have seen it
These fins have raised my speeds, in every course (upwind/downwind/crosswind)
(((I am not sponsord by tectonics or anything else)))