I'm new to this gun thing, I bought a 700 5r in 308 and a vortex viper pst 6-24x50, now I need to order some rings for it I'm thinking I'll get a 20 moa base so I don't know what size rings? Low med or high? Also any suggestions on rings? I've been told Burris zee sigs with the inserts to keep your scope perfect. I read the FAQ but since I must order both online I can't measure.