How can you fit the Talley bases to the rib section of your O/U rifle? I would think a claw mount is the only option.

Visually, I don't think a scope mounted that far forward on a double rifle would look right. I would look at something like a Leupold VX-III in 1.75-6x32. It's lightweight, will sit low, still somewhat compact, and is a very durable scope.