The problem is very small actually
What I like to do is set up the sounds either in combi(D) or prog (F) banks
Say song one.. Piano at F000 I need and organ right after for next verse, Put that in F001 etc etc etc
Now Plug in a second pedal and set it to inc+1 for every press
Problem solved

(for me atleast heheh) Change sounds with your foot every time you need to change to the next. (+1)
Fast and easy way to change the sounds without taking your hands of the keys
If one doesn't have 2 pedals heheh one can always just use the 'inc' botton
Ch33rs
Saga
Edit:
Of course, if you pick songs from the set and not playing song 1,2,3 etc
Write down the 1st sound of that song by the song. this way aswell you will only have to put in the number of the starting sound and use the pedal from there on for that song
Needless to say heheh but I will anyways
I would recommend PCG Tools for easy and fast arranging
He did a kick-a** job with that tool