Hey bearhntr,
I just went through this myself. I changed scopes on my 700P 7RM from a 1" Vari-X III 4.5-14X40 to a 30mm Vari-X III 6.5-20X50 LR/T and wanted to get all the elevation that I could and yet keep the scope as low to the barrel as possible.
I went with Leupold's STD 20MOA Long Range Matte Base (51732) and Burris Signature Dovetail High Matte Black rings (420581) with a -20 insert in the front ring and +20 in the rear.
I can't remember the exact number of up clicks that I have available but after counting and converting them into MOA and running it through JBM, this set up gets me out past 1500yds.
Probably more elevation than I will ever need but I wanted to see if it could be done without spending $300 by going the Picatinny ("Tactical") route. As far as I know this is the cheapest way to add MOA to your setup. Total price; approx. $85.00 including tax & shipping.
I have used the Burris Signatures before on another rifle and they are solid performers. No thrills or flashy name, they just work. JohnnyK