Thanks, good comments. I'm thinking more and more that a 9,3 or maybe 8mm will be my choice. Recoil is not a big issue for me, I've allready got a marlin 1895G in 45-70 and it kicks nice with 350 gr 40000 psi loads. Ive also tried 9,3X74r in a light weight Merkel 141, no problem but quite heavy punch. The 8x57 however, is a very nice low recoil cartridge that should fit well in a lightweight side by side double.
How about Chapuis, are they reliable and well built compared to e.g Merkel? I really like Merkel though....