sailquik said..
Front foot first work on wave boards and slowish Freeride boards, but on fast slalom and speed boards when you come out fast and planning, it is hard to keep the board balanced and driving off the fin if you put you front foot in first. The reason is that the centre of resistance is still well back on the board so to sheet in, rake the rig back and keep driving the fin you need the centre of effort (foot pressure) further back.

Yep, on my freestyle board and wave board I am always front foot first, mostly because I am not focusing on driving off a fin to create lift and speed against a cammed sail. I had a look at my go pro footage from LG to see what I do on slalom/speed gear, and on port tack I do a mix of front/back foot first depending on the strength of the gust I am driving into, but on Starboard which is my fastest tack, I am entirely back foot first. Even on my BIG Bird (Falcon 113 - 69 wide Slalom board) when aggressively pumping onto the plane, once the board rides up onto the sweet spot I flick the back foot in first to push against the fin and maintain pressure, and then the front foot. Feels natural, so natural that I had to look at footage to see exactly what I do. That was an interesting exercise.