Scott, maybe my reply is late, but I have read just now your question. Like AJ said, on the SD1 you can select the jump feature to automatically progress at each fill press from variation A to B then C, D and again A. Or you can simply manually select, after you press one of the fills button, the variation you like. It's not a big deal, really; it just takes a bit of practice (and knowledege of the different variations, of course). It's one of those little things that make playing an arranger different from playing a piano or a synth: it's an art of its own.