Revs are similar, if anything a double will be revvier than a single.
The main difference is the feel, a single feels punchier, a double is smoother.
Orion did HT and HS versions of the 12x1 to get the most out of the old european 12 turn limit. HT is torque biased, for tighter tracks, HS is revs biased for larger tracks.
12x2 and 12x3 were less widely used. If the grip is low, and the track is large, I would probably go for a triple rather than a double. Not much in it though.