Two days ago I mounted a scope on a 20 MOA base. Took it out to the range, dialed down 20 MOA and I was hitting 1 MOA high. It just cants the scope down at the front so it is no longer parallel to the bore, pushing you 20 MOA toward the low end of your adjustment range and giving you more upward travel for longer ranges.
The "G" force is what I recomend. You can get either the 20 or 30 Minute of Angle(MOA) lift. This "pic" rail lifts the rear site so that you do not use all of your up/down clicks on your scope and allows for greater distance and ranging depending on your talents and the equipment you know how to use with the greatest efficiency. I use a "G" force 20 MOA and the Burris "Signature High Z rings" with another 20 MOA. On top is the Night Force 8x32x56 NXS with the NPR2 reticle. This is mounted on top of a Rem 700 "large bolt" tweeked with a Sako extractor, Jewel trigger and fired through a "Dan LILJA" heavy tapered 30 inch 1-10 RHT bottoned rifling gas checked true 308 "free floating"barrel. This sits on a "Mac 3" sniper stock with the Harris "short" bipod. hope this helps you out.