I also have a slip on I take to the range, but have never cut a buttstock or replaced a metal buttplate. I have had a gunsmith replace a couple of recoil pads with these:

http://www.midwayusa.com/product/20...holes-polymer-black?cm_vc=ProductFinding

[Linked Image]

[Linked Image]

“The Savage 99 Pocket Reference”.
All models and variations of 1895’s, 1899’s and 99’s covered.
Also dates, checkering, engraving.. Find at www.savagelevers.com