Yes I think this should save time. I'm really interested to know if the audio and controller devices really are recognised, and always the same one when you restart with the correct cfg file.
Also there may be another benefit. As the window position is also stored within the cfg file. Maybe it's possible the LFS instance will go to the correct monitor as well? We'll see.
BUT... for your test you might like to wait a little, because I am trying something that I hope will do away with any file renaming at all. The driver name and setup is also stored in the cfg.txt so it really is the key. This morning I am trying to implement a new command for the command line /settings=cfg_1.txt so that instead of using cfg.txt it would use cfg_1.txt (or whatever name you choose).
So then you will be able to start your LFS instances with a shortcut (or command in batch file) like this:
LFS.exe /settings=cfg_1.txt
And that will load the cfg_1.txt when starting up. Also any settings you change while LFS is running would also be saved in cfg_1.txt, ready to be used the next time you start that instance.