yeah i guessed that might be the case but like you say a combination of the two help out
obviously using a project per song is going to give you more options and if you don’t mind waiting for the project to load then it could be the way to go for you.
personally i try to stick with one bank per song in my preparations mainly because the sort of live set i envisage for myself is a seamless mix at the same or similar tempo
good luck with it !