As a point of reference, I'm 6', 200 lbs, and wearing a normal winter hunting coat, it fits me just fine. Might be a little short w/o a coat, but it's nothing most people can't adapt to.
No idea about velocity loss, and really don't care. I handload most of my ammo, and a slightly faster burning powder would compensate anyhow.
None of our whitetail deer have complained about a few FPS loss.