I tend to use one registration file per song and name it accordingly when saving it. They can still use the same style files as, like you said, each registration is just the panel settings. For example, I could play a slow song using one.sty, using mainly strings and a tempo of 60bpm maybe but I could also play a brisk song using the same one.sty but using guitars or pianos at a higher tempo of maybe 90bpm.
This eliminates the need to search the contents of a registration.
I use each section of the song in a different registration part number so maybe on Reg part 1 I'd have the into and first verse, the chorus on 2, verse 2 with different instruments on 3 etc.
There are many ways to use registrations, this is just my way. Explore and you'll soon find what works for you