If you can post a bit more info about the gun I can (maybe) help. I just got a '99 and I'm taking the crash course.
Leupold, Burris, and others make a one-piece base that works well. It kinda depends on whether the D&T is factory or not, though. The Weaver two-piece base is supposed to be the hot setup--especially for the typical gunshop D&T.
If the mounting holes on the front receiver bridge are drilled through the "Savage 99" stamp, it's not a factory job. The factory put the roll stamp on the side of the bridge, on the guns they D'd & T'd. Many of the guns that were done by competent 'smiths, after leaving the factory (like mine), have the identical hole placement of the Savage prepped guns. For the guns that were fitted by a "kitchen table gunsmith", it's a crapshoot.