As many as it takes to smoothly go from ANY variation to any other variation. Have you noticed that often, going from the 4 Variation to the 1 or 2 isn't QUITE as smooth as going to the 3 (which is probably what the fill was written to do best)? Or going from 1 to 4...?

What I WANT is something that fools me into thinking I have a BAND, not a machine backing me. I never heard a band IN MY LIFE play the same identical fill two times in a row.

It's the little things that make the difference.