On a low pinion front axle, that's the coast side, high pinion is the drive side. In the rear it's just the opposite. So if a pattern looks good on one side but not the other (which happens more than one would think), I'm favor the side that the pinion contacts when going forward.
So according to the post above, we now know it's a LP rear, we want to make sure the drive side is happy if we can't get both sides perfect.