COL is a gun/barrel/bullet variable and can be "assumed" from loading manuals or your buddies favorite load.
I have never gotten the accuracy out of a jacketed SWC as I get from a cast SWC in .45 Auto. Loading data comes from manufacturer and other reloading component companies. Not from me and not from your buddy.
I show the following:
Jacketed SWC: start is 3.9gn and max is 4.3gn.
Lead SWC: start is 3.6gn and max is 4.3gn
This is too tight a range for me to want to play in, especially for a jacketed bullet. I only load powders that show at least a grain between start and max and I KNOW that Clays peaks quickly and has an almost hockey-stick pressure curve, so I don't use it.
If you can, look at 231/HP38, AA2, AA5, Bullseye, or Red Dot. These powders have never shown a spikey pressure curve for me and all produce great accuracy. Solo 1000 is a very fast powder, but it still has about a 1 grain range from start to max.
Clays and TiteGroup are "in" powders that I have simply NOT been happy with.