I thought about that, starting heavy with yellow, cleaning the surface, then switching to a BBW for mid polishing. At first it seems like it might save some wear on the yellow coticule. But if you've already got a slurry built up, and all you need is to dilute that, I'm not sure I see the benefit of changing stones.
Well, time and experimentation will tell. At this rate I'm going to need a larger chest to store all of my rocks lol.