[johnfowles]

A very pertinent question
And one that I well remember posing to Mike and Terry after one Count Basie Theatre, Red Bank NJ concert when they were seated on stools in the bar at The Molly Pitcher
Whilst they were cagy in their replies dear Terry did confide that sometimes Gord came over to him and conveyed the title of the next song: if so Terry would then pass it to Barry who could relay it to Rick but their main answer was that they could tell very quickly as soon as Gord began which was to be the current song.
And yes the songs in rotation are quite limited but I am far from sure that there are a mere 4 standard setlists.
And yes Barry told me after one concert that he rescues from the trash bin after each concert a rough setlist made by Chuck which he then transcribes into a master setlist record book.
After one concert I explained to Barry how I used a mnemonic memory aid method ("one bun two shoe" etc) to recall a setlist myself and after the following concert he passed me that evening's setlist (on yellow legal paper I recaII)
afer all these concerts however I do not remember ever hearing any one of the "Orchestra" starting the wrong song (very occassionally Gord yes) (and at least once {at Massey} Gord launched into a song sung earlier) (he later tried to claim that it was deliberate as the concert was being recorded and the first rendition was not good enough)
your mileage may vary of course