I am kinda late on this one...GLAD to hear it worked out good for you!! :grin:
I'll add this in case someone else needs to do this, I have found a super easy method to cut grooves in bases!!
If you have a DREMIL TOOL its easy!! It comes with a few bits, one is perfect for cutting grooves!! Its the 1/8" round bur.
Here is how I do it, remove the base and place in a vice. With a square, align the DREMIL with the square in the proper position for the new groove. turn on the tool and grind to the desired depth. this works especially well for the burris rings as the thru screw is actually round, not square as the factory grooves are. If you are careful, it will come out perfect!! Hit it with some alumi black or a Black Sharpie and your done!!
Good luck,
CW