You can grind any pad to match the curve of the buttstock but if unskilled you may need several pads to get the hang of it through trial and error.
It took me two attempts at grinding to match the curve of my 24 gauge's butt.
When looking at adding a pad you need to consider how it will effect the handling in terms of balance. A pachmayr or silvers pad are both very heavy and will add weight to the end of your gun and can easily make it butt heavy. You may have to hollow out the butt some.
Another course of action I have pursued is to use Italian made Cervellati microcell pads which are roughly 1/3 the weight of the same thickness rubber pad. They come in both black (available in the USA from Hastings) and brown (though for the brown you need to find someone in Europe who will ship it to you)
Another challenge with the Cervellati pads is they require a finer grit sanding belt than the normal rubber pads which led me to do it myself as the local guy in Kansas City was not interested in William Tell Hunting Club, Moosehead Lake, Maine taking the job.
