I always split the belt loop. Belt goes through rear slot on holster, then trhough belt loop, then through front slot on holster. Weight doesn't cause as much sag this way and it does not slide around.
Ya know I misread your first post I thought ya were talking about the ones that have one slot in the rear and two in the front at different angles. Thats what my response addressed. I missed it that you were talking about different cants on the front and rear slot. Those have always baffled me too. Unless your belt is very pliable single ply, or much thinner than the slots I'd think ya were gonna get a wad behind the holster.