Nothing is "safe" when it comes to shooting 140 year old guns.
If you can get some 32 Colt brass and drill it out as described on the internet, and stuff in a .27 Hilti or Ramset cartridge, topped with the right sized/lubed Ball (less resistance, lower pressure), you should still probably fire the revolver from behind shelter, held in a vise and triggered with some string.
The biggest problem is, the weakest cartridges are not readily available in Canada. .27 Hilti's weakest is White in color. Ramset, Brown.
Ramset .27 weakest available -- Brown -- is still #2 power. So where's #1? Lately, Hilti .27 weakest available is Green (#3 power). Sure, a healthy revolver will hold up, with a light ball load. One with a flawed cylinder, one fractured by the last owner, one ... well, you get the idea. Yikes. Any gun might fail, but one over 120 years old ...
There are white and brown Hilti somewhere, and I have never seen or heard of white Ramset, though there may be such a thing in America. Those would be "safest".
One could always machine the casings from steel to reinforce the rickety revolver cylinder walls. Still, to keep more fingers, the best plan is to fire slightly undersized and lubed projectiles and pay attention to what's happening. I have managed to ruin a revolver cylinder (not a black powder gun, a modern, stainless one) and it was by following advise like you're reading now. The lesson I learned? Measure the cylinder walls before you shoot anything, get a good digital caliper and have someone teach you how. Shoot a "safe" load and check. Keep checking, if things change by even 1 thousandth, stop. Revolver cylinders will start to stretch, like mine did, well before they fail entirely. That's modern cylinders, made from modern alloys.
Keep pressures low, don't shoot large, heavy projectiles out of .32 rimfire revolvers. Keep it light and you should lose less fingers than if you use a heavy load with a big charge. With antiques, I'm sure part of the thrill of shooting them comes from looking at your intact gun, held in your intact hand, in amazement as the smoke clears.