mounting man,

It's your rifle so what you do is ultimately your decision. Personally I wouldn't cut the stock and retro-fit a butt pad as it would ruin the aesthetics of the rifle so to speak and decrease the value, but it's yours and if that's what you choose to do, so be it.

As far as no one giving you what it's worth, you'll probably never get full value because it's used (even slightly) and it's not rare. Not to mention that in today's world, everyone wants something for as cheap as they can get it.

Seeing as how you have a lot of time between now and next Flintlock season, my suggestion is this...

If you know someone that's a very good woodworker/carver, kind of like someone who restores antique furniture or maybe someone that builds custom rifle stocks, you could have them make you a retro-fit butt plate from quality hardwood that fits the factory contour of your rifle but with a squared end like a regular rifle stock has. You could have them cut course checkering or horizontal lines in it so that it wouldn't be slippery when mounted to the shoulder. You may even be able to have something made from black nylon so that it looks compatible with the iron furniture it has now.

This alteration will more than likely change the LOP a bit so it's something you'll have to look into before plunking down any $$$. I would probably trace out and cut a chunk of pine for a "filler" as you stated and then duct tape it into the crescent. Then you can shoulder mount the rifle to find out if it's going to fit you.

On a side note... I've shot a number of the GPR's and although I'm not enamored with their deep crescent style butt plate, I never really found them to be a hindrance. Seems like the first time I shot one, I kinda "naturally" found the pocket it should rest in and from thereon whenever I shoulder one it seems to just fall into place...but that's how it works for me.

BPS