Ok, sorry for drifting a bit off topic here.
Prime numbers are nice. Although I like to maximize the number of runs before any repeat. So instead of 5 steps, 15, a multiple of 5. Instead of 7, 14 steps. Gives longer "phrases", less obviously 5 or 7 (with 15 I could phrase it distinctly as a 7+8,) and less repeating. 5x7=35 runs, 14x15=210 runs.
I ususally use the highest step count for sequencer 1 of each layer, when making poly-rhythmic stuff, because of the step "rests" which makes for rhythms.
Something simple like this, to start with:
Layer1
Seq1 - 15 steps
Seq2 - 14
Seq3 - 13
Seq4 - 12
Layer2
Seq1 - 14 steps
Seq2 - 13
Seq3 - 12
Seq4 - 11
Seq1 - Osc1 pitch
Seq2 - Osc1 pitch
Seq3 - Osc2 pitch
Seq4 - Osc2 pitch
If I want something straight forward to keep the "beat" of 4/4 (16 steps) I use something outside of the Rev2, but if the sequencers are set up well there's usually no need for it.
I route the sequencers to other stuff as well, in the mod matrix, sometimes even a sequencer with negative amount to the "other" OSC, for example Seq2 - Osc2 pitch- (as it's already routed to Osc1 pitch+) = contrary motion, but because of the amount of other pitch modulations going on it may not be perceived as such, at least not every run.
As for what numbers to put in... Depends on what you're using it for, but trial and error is inevitable for the best results anyhow, so just go at it. And therefore an EDITOR is key for these things, being able to tweak all 8 sequencers, 8 LFOs and the mod matrix simultaneously as you go along (ie the stuff more or less "hidden" on the front panel).
This method could of course be used with PAN as destination as well. Maybe Seq1 and Seq2 to PAN directly, and Seq3 to control the amount of an LFO which in turn modulates PAN, for some movement (on some of the notes) in the stereo field.
More complex modulations take more effort, but are also more rewarding!