I've been using an old bridle on the horse I just bought, which the owners sent with him. It fits him fine, but it's not really a regular bridle - just clip-on cheek pieces that attach to a throat latch and browband.
So I tried my old hunter style bridle on him - which used to be used on my old Quarter horse. On my new guy it's up on the shortest holes, and might be a hair loose on the bit - I'd probably pull it up about half a hole shorter (with a hole punch) if I was to use it on him. The brow band sticks out an inch or so in front of his head. The nose band with the strap around his head on the shortest hole is roughly over his nostrils, so it would definitely need a hole punched and a LOT of the strap chopped off to keep it from banging him in the face.
So I got a new dressage bridle - because we're starting some dressage lessons this week. I decided to try a cob. It seems to "just" fit on all the longest holes. The browband is slightly tighter than I'd like, but only a hair. I'd like one more hole on the throatlatch. The nose band is probably ok, or I might lengthen it one hole if that was available. There isn't much leather left for punching new holes in that one, though, since we're on the long end of it.
Are full and cob really that different, that I could be stuck "in the middle" of the two? Or is it just the difference in bridle styles causing that? Should I try a full size dressage bridle on him and see if that gives us more to work with, or is it likely to be as oversized as the hunter style full size?