Persuant to my other thread regarding 20MOA base& ringset for my Sako with dovetail, I found that the simplest solution would be to use Burris base with Signature rings and Pos-Align Offset Inserts. I'm not familiar with the set-up. Do I need to order just a front or rear insert, or do I need a set of front& rear inserts? With a regular scope mounting, I know that it's critical to have front and rear rings centered so that the scope tube is not stressed. How does the insert system achieve this centered scope rings allingment?