A little experience with slip jigs, on both bass and guitar. Not sure how valid the purists will consider this, I think it depends on the tune, but I noticed that I've felt the beat on 1 and 4, or 1 and 7, sometimes alternating, sometimes not. I don't generally stick to a 1, 4, 7 beat as it tends to turn the feel more towards a single jig if repeated too much.

Peace, Mooh.