Go for a Raceboard in 4/14 Knots rather than on a 320 board.
For the same weight, with a "heavy" Kona and 9.5, i start to plane ealier ( little bit ) than with iSonic 125 and 8.5
Take an old Raceboard with a big Fin and try your 10.3.
To big on IMCO, but it will work on :
- Mistral Equipe II / Pan AM
- F2 Race 380
- Fanatic Mega CAT
And on the new ones to
EXO WARP 380