My approach is: one performance per song and I use the same basic performance for each song and make minor tweaks from there (little more or less delay, a different time signature in the delay etc). You can set the bpm for each performance.
However, I have not found a way for global adjustments across performances for amp profile parameters like gain and volume. Until the editor is out (for me: not until it is out of beta) You have to do that on the profiler, for each slot in the performance. the most efficient way to my experience is to create a rig with the desired profile settings in your library and copy that into each of the desired amp slots of the performances you want to change.