Diy wing foil Board

That should get one the foil very quickly… lot of surface on the bottom (maximized by your straight rails), no quick change in rocker (as long as the first 10-15cm stay out of the water) and no big radius rounded corners, sharper corners release water better, too rounded tend to stick.
I’d just be concerned by the completely straight rails seen from above… does that let you taxy upwind?

@Mat: couldn’t try it out yet as I’m waiting for the delivery of a Takoon Wing (July 2021).