I have a Remington 870 supermag. What choke would I put in if I was deer hunting and wanted to have my first shot be a slug and my second be a buckshot load? I don't have a rifled barrel. And also, is it going to hurt anything to shoot a slug out of a tighter choke, or does it matter? Thanks. I've never deer hunted with a shotgun until this year and so I don't know any of these things.