I think it will depend of your foil and board. I have only foiled twice and in light wind but all I do is to put my front foot in the strap and rear foot wherever it feel comfy, sheet in, put a bit of weight on the back and of I go.That was using a fairly big foil and a formula board so no problem of stability. When going, I do put some pressure on my heel to go upwind and to get the board counter heeling as you can see my toes pointing up on this pic. Going downwind, I just keep the pressure neutral on my feet.

Again, I have only tried that gear in light conditions only.