Yepper Depper
I too was infected by the very infectious "Conversionious" infection. I also have a pair of 1860s, converted to 45 with the most excellent Kirst Konverter and Ejector assemblies. They work a treat. I also found the "perfect" cartridge in these guns to be the Cowboy 45 Special case. I however, shoot either 160Gr RNFP and APP, or 130Gr Barnstormer and APP.
Now for the CAVEAT: My donor guns are/were Pietta. Hogging out the loading channel for the gated recoil plate is/was no big deal. I can switch back to a percussion cylinder although it looks hokey as hell. I do consider the conversion with Loading Gate et all to be one way.
For those contemplating shooting suppositories thru a Uberti based Colt second gen or Signature, I would consider using an R & D type cylinder. Yes it can be a nuisance to reload, but once practiced, I find it to be no big deal and you preserve the original gun. Well fitted, removing the barrel assembly is just no biggie. Same same applies, you want the unit for Uberti. The guns are, after all, gussied up Uberti's. Well set up, when switched back to percussion, the gun lends well to a Cylinder Loading stand such as the Tower of Power (Shameless plug for DDD)