I’m not sure what you’d be notating.
For quick turnaround rehearsals, I usually have a sheet (chords for the song / arrangement / whatever I used to learn the song) up.
I make notes on that.
If you’re talking about noting things that you like that happen more spontaneously, I don’t know how I’d note that.
What I’d recommend is just recording it on your phone.
If something cool happens, maybe make a note of the time stamp, then go back and check it out?
If you have a more specific for-instance I might be able to help more.