I lost a ton of time on this star because I can't find a consistent way of doing it and I end up running out of time. Does anyone know how consistently do this star?

Well, there is no way to do it consistent because the crab placements are completely rng based. However, if you jump while in rock form and press Z, you stop immediately. Do this when you have few crabs left and it makes it a lot easier.

Well, The entire thing is RNG based, so you cant really get consistent at BB Comet.