Thanks for the run down, hmmm, I think 76 will be the way to go as I plan on using a 5.6 S1 a bit more than my overpowered/powered up 4.5 and hence think that the issue of "In quality overhead waves and nice powered up sideshore the 76 might start to feel a bit big, especially if you're on the verge of being overpowered at the same" won't arise too often that i'll be upset that I didn't get the 71. whereas "5.6 on the 71 is possible but it will be overloaded a bit" could frustrate me as it'll occur more often.
If I lost a little weight (to say 68-71kg) do you think 5.6 would still overload the 71? - this may motivate me to loose some weight
and keep it off
Also would changing the fin set up by going to
# Quad 15 x 2 + Quad 11 x2 or # Quad 16 x 2 + Quad 11 x2 from # Quad 15 x 2 + Quad 12 x2 on th 76 as spec'd help when it does begin to "feel a bit big"