RE: That pesky rear footstrap
I agree with Roger. Get those footstraps out :-). I have the FF 158 and on the weekend was sailing overpowered on a 7.6 and even with my 70cm Drake fin, (only one I have) the board maintained great control.
I am amazed how well these boards sail with smaller sails. It must have something to do with the very short length. I was flying over chop which would have given me some problems on my 66cm wide but 270cm long RRD, even with a HUGE 70cm fin hanging out the back :-).
I have also used a Ft158 with a 6.5 and 64cm fin in flat water and had a great time.