Leading edge, trailing edge, … This post should be useful to you:
The parameters that matter: airfoil section, profile thickness and thickness to chord ration, same thing with front wing airfoil sections… demonstrated with figures here:
Today, in kitefoil, to go beyond 45 knots (70mph or 80 kmph) without motor (just wind), the best mast thickness is ~11.6mm, built in UHM carbon (Ultra High Mofulus). That’s half the 2008 Carafino kitefoil mast thickness (22mm) which had a very draggy elliptical airfoil section.
For me, the ideal efoil or kitefoil board should look like this (half joking 
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