For sizing: same as sneaker and flats.
I didn't have a problem getting my ankle in (though embarrassingly, I did when I initially got them and forgot to take out the cardboard shapers (they really molded into the boot!). The ankle is a bit stiff (hence the minus 1 star). I didn't find the calf to be any tighter than the standard boot. Wore these puppies in NY in the late winter slush and they were awesome!