We don't shoot shotguns now -- I've started her off on the pistol and the rifle and have been trying to impart what the Marines have imparted onto me. Neither one of us is big, so in maintaining the proper shooting stance while facing the target, the shorter the longarm the better.
You may be under a misconception, the natural stance with a shotgun is with it at diagonal to your shoulders. With a face-on stance, your left arm is over extended to operate the action (and you maximize yourself as a target). Perhaps you should beg, borrow or rent the guns you are considering. A local gun club may have an introduction to shotguns
class and provide a bevy of trial guns. Some actual trigger time before you make your selection is always a wise idea.