Thanks for the suggestions. The Parker Repro idea is on which I had not considered, but, while I have never held one, I am more drawn to lighter guns, and DTs is a must.

So, I am looking at a Griffin & Howe Arrieta online, which seems to be reasonably priced and in decent condition, except that the hand detachable thumb screw does not seem to be properly indexed. Instead of being roughly parallel to the barrels/action when tight, it sticks up at a 35-40 degree angle. Sort of looks like it may have been over-tightened, but I really don't know much about hand-detachable locks. Is it possible it was over-tightened? Is there a fix for that?

Also, any way to tell the age from the serial number?