I have a Leupold 1X4 and love it. At lower mags I can actually see the end of the barrel and swing on running game like you would with a shotgun. When the woods are wet and quiet, I like to walk slowly and jump deer from their beds, using my semi auto with the 1X4. Practice keeping both eyes open while shooting.
I realize you are asking for shimming advice. Just thought I'd share the merits of a 1X4 scope. Hope you enjoy yours.