On torches, that was all just approximation I could find except the number of ticks they last, and match with what I felt they did.
I'll started up a new game, and both settings in Options for Auto-Key Usage will automatically use the appropriate key. It's honestly a QOL improvement I doubt anyone would actually complain about, but I definitely appreciate the option to play OG style. Auto-Jump also happens regardless of the setting if you hold the jump button down and hit a ledge. This is more just an FYI for you, since the settings work correctly as if they were turned on.
I noticed in the Appdata folder, there were files for what appears to be BOTH underworlds. Does this work for UU2 as well if we set the path to that? Or not(yet?)?
Either way, thank you for the responses, glad to give feedback and observations, and thank you again for this. I'll just have to get into the save file for my own education and see if I can't adjust the things to make myself happy.