ORIGINAL: retrieverman
It sounds like you have already made your decision to use a 2 piece base, but I would go with a dual dovetail base. I prefer Leupold bases and rings.
Not really. From an engineering point of view it seems a 1 piece mount will be better, but I have seen the B-SQuare
https://www.swfa.com/pc-7905-639-b-square-interlock-one-piece-base.aspx one and I am afraid it will make it hard to go to the magazine.