Would proably go for a light load. Not real found of fillers, but you could work out just how far that rammer enters the chamber, add in the diameter of the ball, and get a good diea what the minimum powder charge would be that would offer some copression when that ball is seated to the limit of the fammer. PROBABLY about 22gr.
Colts are all hung together on that cylinder pin...cylinder and barrel ride on it, held on byt the wedge. Everything depends on that pin staying tight to the frame (it's threaded into the frame and usually pinned or swaged in place (or both).
Steel-in-steel threads are stronger than steel-in-brass but some of the stretching can be traced to pwople who drive the eidge in like they are hammering tend pegs, but most of it is from the force of the ball meeting rifling. Load lighter and don't pound on the wedge and it will last a very long time.