Did some weighing last night of my gear for future reference. Was very surprised at difference in weight of fins and straps:
Board only, then Board, straps and fin:
Tabou 105 6.8kg & 8.3kg
JP FSW 84 6.3kg & 6.9kg
That's 1.4kg vs 0.6kg for straps and fin.

Ok, the FSW only had 3 straps vs 4, and a 25cm fin vs 32cm, but that doesn't make up for a difference of more than double. (And to think I was worried about a possible 50ml of water in my Tabou - I'd be better off chucking one of the rear straps!

)
(Yes, the straps were all bone dry, and reproducible measurements were made on electonic scales.)