Are you talking about buying two recoil pads; screwing one onto the buttstock and then screwing the second one onto the first one?
If you are, there would be several problems.
the LOP would be about 2" longer than the original, making it awkward.
When mounting the second, you would either...
use LOOOOONG enough screws to go through the first pad which would essentially eliminate the benefits of the first one and you would have two screws extending into your shoulder when you pulled the trigger or...
screw the second pad into the first pad. In that case as soon as there was any lateral force it would rip the screws out of the first pad. Which is what one of your fears was.
It would look kinda' cheesy.
and lastly what the hell are you shooting that you need two recoil pads...a friggin' shoulder mounted howitzer?