So it still isn't crystal clear what goes where in a swap and how to turn a series of swaps at the end into a 3-cycle. So I started to experiment with a solved cube. But then I got sidetracked by a whole new idea. Instead of getting an edge surface to position 1 to do the swap, what if I got it to A then moved the M slice down in the back to put A and 3 on the bottom for the swap? It makes setting up the swap quicker and easier in a lot of the cases.