TX, we rotate. With our first two ME moves, we generally make one a high partial and one a low. We might do 2 board this week, then our second move would be JM's or something like that. Then a few weeks down the road, if we're doing 4 or 5 board, or 2nd move may be somthing to work the bottom part instead.
Too answer your question....we do one board each ME Bench day, and then do a different board the next time.