Just received my new SAKO A7 in a 300WSM. Came with mounts, rings & Burris scope. When I went to level the mounts prior to leveling the scope, I found the mounts were not level compared to each other. How do you determine which of the mounts is closest to being level to the receiver? Once that is determined, what is the best way of leveling the second mount? Shim or sandl the mount?