Ditto on what others have said about powders, AA#2 is a bit fast, IMO for such a large case you'd have a very small load before you had enough for an overpressure load. AA#5 is listed, though.
If the 185 grain XTP bullets you speak of are the ones listed in the Hornady manual for .45 Auto, I doubt you can make them work in the .45C. The 185's are 0.451 diameter, and do not have a cannelure to crimp into. Standard .45 Colt bullets are 0.452 and have a cannelure, and should be roll crimped. The .451's would probably not have enough neck tension and would set back, even if you taper crimp them.
I tried as an experiment to load a couple of 200 grain .451's for my .45C, and could not get them tight in the case. I also load for .45 Auto, so I have those bullets on hand, but I only use the cannelured 250 grain .452's for .45C loads. I shoot fairly mild loads, my .45C gun is a S&W M25.
