So I have ruined the non-drive side crank on by beloved fixed gear conversion, and also stripped the bolt trying to get it back on. Sigh. It's an early 80s vintage campy BB and crankset. These parts are tough to find, especially in 170. Do I have another option as far as fitting a new crank? I mean, I don't even know what to order since the parts are pretty much unmarked. (see below) I've heard that only certain square-taper cranks will fit with older campy stuff.

On a similar note, is it better for crank health to use a smaller ring combination like 42-14 than say 53-17?