I have a Tikka 3x Tac A1 with a 0 MOA base. My scope is a Vortex Razor Gen III 6-36x56. When I bore-sighted & zeroed everything went well. Following my zero I checked to see how much elevation I could still dial up. The result was 58 MOA. To go past 1450 yards without holding for elevation I’ll need to get a different base. I plan to put a 20 MOA base on the rifle and then re-mount the scope & re-zero. This is where I am not sure how to proceed. Should I re-zero using my current 0 MOA base zero or should I start from scratch and re bore sight with the 20 MOA base then zero from there? Thanks in advance. Jim