Re: Cleat placement.
Interesting question. What I am seeing in these responses so far is that the ball of the foot is preferred for climbing but the DH bias is to be more flat footed on the pedals. I would challenge that thinking a bit. If you compare to other sports, wouldn't we all want to be somewhere near the ball of the foot for the downs as well? Seems all sports require an aggressive athletic stance, and flat footed is not that stance. Skiing, snowboarding and every sport that requires running demands an athletic, somewhat ball-of-the-foot stance. Granted snowboarding and surfing also involve heel weighting - but I think those sports are an either/or proposition with little time spent flat footed with the weight directly over the arch.
Mt biking has a unique aspect to it in that when we need to be our most athletic selves (ripping down a hill with lots of rocks, turns, roots, ruts, changing surfaces, etc) we have one foot forward and one foot back. For most of us, it's the same foot forward all the time (I am regular foot - left foot forward, which is harder on your crank arms than goofy foot, as the right crank is always getting tickled by the chain). Should we put one cleat further back on the forward foot to compensate for this?
My thought - stay aggressive and athletic in your stance for DH. Unless you are leaving the pedals and coming back (real tail whip), in which case, you are crazy and have entered another realm.
I wonder where pro DHers have their cleats? Now I'm gonna start studying all of the pictures to see.