feet back, wax wax wax. remember to lift your nose when you're riding pow. Turn on your back foot alone if you're sinking, wheras on hard pack you can make front foot turns. As you get more used to it, and start going 35+ mph, you wont have to lift your nose anymore.
ps: tell tail sign for need wax is the crystal buildup on the bottom of your board after a run. Are the crystals interconnected? then you need LOTS of wax...
Board length in pow really depends on steepness and center of gravity. If you're riding steeps-wasatch front chutes etcetera-you really dont want a long board unless you're really really good. (control keeps your head away from the rocks...) But if your cog is real low, you'll need a bit longer deck. I find that in my experience riding, board length is totally overrated for floatation versus mere waist, tail width, and nose profile. In 94 when boards were really stiff pos'es, you needed a longer board because you just couldnt flex the nose up for beans. My circa '94 fat bob plank, a 168, has the same waist as my circa '97 jamie lynn XL, which is a 158. It is my personal opinion that most people havent really riden that many decks to realize that length is not the end all or be all, and there is a leftover conception from the early days that length was the only way to make a great powder stick. For example, winterstick, a company that pioneered BC snowboarding along with voile in SLC, used to make 210's. Now the same model is 185. Boards are shrinking...but salesmen don't know it. (think about it: if you do a lot of BC, you generally work as ski patrol or at a real job. its not for amateurs. people in *most* gear shops are...)
we were in another knee deep day, i'll put some pictures up on wednesday to show the terrain we're riding.