I just measured 5 stocks.
Speed feed stocks are 1 1/2" from the pad
Rem stocks are 3 - 3 1/2" from the pad.
And the one I drilled is in between ,about 2 3/8"

Pick a spot that is at least a 1" ,that looks right to you .
Drill a hole just smaller than the screw shank ,I then use a bit slightly larger and countersink the hole .
I use bar soap on the threads to ease the instalation.

Johnch