Buzz - some shooting schools have tryguns that can be altered to fit and then shot. You may want to ask around to see if you can locate one - that would give your friend a chance to shoot a gun that fit her and give you an idea of how much stock alteration may be needed.
My son's Benelli Montefelto has shims that allow for a decent amount of change for cast and drop - plus it is light but also manages recoil well. This is the first and likely last semi I will own but it has functioned well and was the right tool for this particular job.
I would recommend an Italian 20 gauge over & under . . . can be bent and cut down to fit easily
I would agree that an Italian OUs would be a good candidate but many of them have throughbolts - don't those limit how much bending can be done?
