ORIGINAL: earlwb
I don't think you pictured the method yet, One side of the piece of aluminum matches up to the through hole mount and is threaded to fit the engine. The other piece uses two short screws that match up with the muffler. Outside of the two are two more holes that one side is threaded so that you can bolt the two halves together to make the bridge adapter.
Instead of using 6 short screws, you use four short screws and two longer screws for the engine.
I haven't had to do it myself yet. But I will eventually.
I jumped the gun, and hadnt thought about it enough. I was looking at it as using 4 screws instead of 6, not considering bolting the two halves together and seperately bolting into the engine and muffler. I was originally thinking of 2 screws into the muffler and adapter, and 2 screws through the engine and into the adapter holding it all together and to the engine. Going at it this way would just need the muffler offset enough so the screws dont interfere with one another.