The FSW rides a little bigger that the volume suggests so the 78 l would probably be ideal for your wight and max sail. Your weight plus rig and Wesuit you may be in the water up to your knees. So if you wanted an extra sfety factor then next size up. But need to consider which sail you use most and your smallest sail. Des
You should use volume as a rough guide only...better looking at width as this will give you a better indication of the boards performance.
I weigh 90k and use an 88L acid in 20-35 Knots. It' 56cm wide)
For lighter wind I use a 96L Fanatic freewave which planes at 14 Knots and is still comfortable up to 25 knots. It feels quite short but is wide (61cm)in the mid and has a wideish tail so can take quite big sails but is still quite loose and turny and it jumps and carves nicely.
The point is that one board will work perfectly with a 4.7 sail in 35Knots and the other will blast with a 7.2M in -15 knots. They ride completely differently but there's only 8L difference in volume.
