No plans ask you to fill out a form with your height, weight and shoe size. Your bulkhead distance should be determined by your needs. Personally I like foot pegs because I can set them so my thighs are tight against my under deck or thigh braces. Occasionally when I paddle I take my feet off the pegs for a stretch. I find I need that. I do have one boat with padding on the bulkhead for my feet but find myself angling my legs if I want a stretch.

I like my back bulkhead with a little room behind the back cockpit rim. I shove things there. (extra water bottle) etc. I think commercial manufacturers like Valley, NDK etc, are always preparing for WWIII on the water (that's what they have to do). I have dumped plenty of boats with room behind the cockpit with no problem. I case you don't understand, its about having a boat drain fast during a rescue.