Have you considered a replacement stock?

Likely a more costly option, but if you were to fit a new stock to the ol' MS the original could be preserved just as it is (able to re assemble if desired) while having a more suitable stock for continued use.

One could even have the new stock built to suit regarding length of pull and cast.

This may border on MS blasphemy, but I've long wondered how a tastefully done laminate or even synthetic stock would work out on a Mannlicher Schoenauer.