You can set PA3X to immediately change sound or style when the bank opens, or you can set it to change only when the sound or style is selected.
It's easy to recall Songbook entries by number. You can assign numbers to any or all entries. For example I use 3, 30, 31, 32, etc. for waltz entries, 4, 40, 41 etc. for 4-4 setups, 6, 60, 61, etc. for 6/8 entries--you get the idea.
Not sure how easy it will be to remember where the numbers are on the touch screen, but they are pretty large. I think you could do it without sight, but not certain, and my keyboard is not at home.
DonM