I have fitted several grind-to-fit Pachmayr pads on various rifles and shotguns. Very good pads, but unless I'm replacing an older pad, I always shorten the stock to maintain the proper LOP.
I've never tried one of their pre-fit pads, as they wouldn't fit anyhow after the stock was shortened. Get one and try it for fit before you actually mount it.... if you don't like the fit, just return it.