well you wouldn't believe it des but i got to stick my n/p 7.3 on a isonic 111 today 15 to 20knts with the largest drake fin that comes with the board maybe a 40

, then stuck my c3 36 on (as you would if you was trying a board out) it was a tad small (38 would have been great)in the lulls but in the gusts sweet'as
most of the day i was on the ca 55 and ended up on my 80lt

,with the 7.3 being a bit heavy for the board but in the gusts you could fell the tail lift in the fin
des if you want to give your 38 a go tomorrow get down there early cos it looks like you will be haveing a fin and sail change towards the end of the day
either way let us know how your 38 goes