Corbin,

I do not have a Merkel, but I follow this thread with great interest.
I think too much space is devoted these days to big bore doubles, as if only DR's in a Nitro Express round bigger than a .450/.400 X 3" are good enough to be considered. Sometimes I find myself thinking (or better, dreaming) about these calibres, of course, but the truth is that small bores like a 7X57 or a .303 are much more usefull, unless you hunt more buffalos than deer!
I came to the conclusion that some of the most interesting rounds for a small bore DR would be something like a 7X57R, .303, 8X57R or even the good old .30-30 Win! My double, which is now in the middle of its contruction, is based on a 12 gauge frame, so I decided on a big bore (but no NE: it is a .444 Marlin). But if I had a 20 or a 28 ga action, I would sure chamber it for either the 7X57R or the .30-30.
I hope you find someone with good experience on the Merkel rifle.

Regards, Fred