I thought binding placement is determined by boot size, rather than how
many plastic binding pieces there are.
Two speeds is tricky, because one is always going to feel lagging vs.
the other. My experience was the front determines the initial feel of
speed. I'd start with the faster there, otherwise why not go equal. The
other thing to consider is whether or not you're lower legs are ready
for "very slow." I got injured trying it, and didn't feel a thing
wrong until afterwards.
Gene