So I put the padding on the floor and a case of beer on top for a few hours, its pushed down just enough to fit quite well.
I hope the case of beer was empty, cos it would get awfully warm after sitting out for a couple of hours!
You'll find that the cheek pads compress over time, so they may feel tight initially, but will start to squash after a few rides.
Next up is the epic adventure of buying boots!!
Good luck with that!
Rule of thumb, the more $$, generally the better. Spend what you can afford, and invest in the better known brands. Remember, they are not designed for walking in, so stomping around a show-room is not a good indication of how they will perform. Look for good ankle support and enough room to wriggle your toes, but not let your foot move around inside. Also consider good protection for your shin, and that the buckles don't stick out!