I have an oppurtunity to get a brand new Nightforce NXS 5.5x22 with zerostop at a great price and I would like to get your opinion on a few things. 1- 50mm or 56mm- Reasons behind both (I know this subject has been beat to death) Just trying to make the best call. 2- What rings and bases? This scope would be origanlly mounted on a 257 wby and then end up on a 6.5 or 7mag at some point. Is it worth putting a 20MOA base on the Weatherby rifle?