Hi Dr. Sassi,
Yeah, I guess Photoshop could be a way to do it. I'll give that a try. Thanks!
I put my screenshots in a Dropbox folder here: https://www.dropbox.com/scl/fo/jjibiu7y0e1nrqry1vfux/AC1X2nHA88gtkg2P1t-NRJQ?rlkey=dc7jnarunqx4lxhxfxcr6fr44&st=w7823bzv&dl=0
bake01 and bake02 are the way I'm working now. Then I put my proposed "Material channel splitter" node, which I'm guessing doesn't exist. Honestly, if it ever COULD exist, I think this would be invaluable for people who are making assets for games, AR or VR. One of the things I've struggled with most is properly baking texture images to work with, say, Unreal Engine, and I feel like I'm not the only one.
Thanks again for your time!
-Greg