I wouldn't recommend using Estes StarTech starters for clusters. Maybe 2 motors, but no more. The old Solar Igniters were better for clusters, the pyrogen burned faster. I now use BP starters from MJG technologies (www.electricmatch.com). They're low current, easily can light 7 motors on 12v, not sure how many the PSII controller could light, perhaps I'll test that.