I have an 870 express pump 12 guage with a 26in barrel. I am looking to modify it so my girlfriend can shoot it. she is just over 5 foot tall and the gun is too big for her. My question is, if I buy an 870 youth stock, will it fit my full size 870? or, can I just saw off a few inches from my stock and add a new pad? any ideas? thanks for the help