Before I did that I would patiently search out a correct butt plate. There's a guy in the Czech Republic who sells on eBay and GB quite a bit who specializes in BRNO and CZ stuff. I would suss him out. I betcha he can fix you up.
Short of that, how about a thin red rifle pad from Galazan? It would require flattening the end of the butt though, but would look better than what I'm envisioning you're contemplating.
