I feel like for a long time 75cm was the standard for surf foiling then we started riding higher aspect fronts with bigger spans in the 95cm range and inorder to surf those more critically we ended up with masts in the 80 cm range.
I find that esp for short period prone every CM of mast matters - shorter giving better bottom end by keeping the foil higher in the water column closer to the wave energy. With my 915 ish cm 930 I found 78cm(board to top of fuse) to be my sweet spot based on our specific wave energy.
I feel like shorter is a little more responsive also as the arc to wip it from one side to the other is smaller and covers less distance.
Now I’m finding I’m spending alot of time on a much smaller front - 680 sq cm at 790mm span. I’m thinking it might be good to creep the mast back down 2-3 cm since I don’t need the depth to keep the tips out as much and gain a little more responsiveness transitioning the foil as well as a little bottom end taking off in the smallest conditions.