Sorry I can't provide any pics of the process of chopping the engine. I did it pre-digital camera age.
All I can say is that each engine will be different, so its just a matter of selecting a suitable place to make the cut that will leave some suitable points to drill and tap for the bolts that will hold the covering plates on. A band saw is a good starting point to get rid of most of the unwanted metal followed by machining to get a flat surface for the plates to bolt to. I didn't bother with the original sump plate, I just bolted on a piece of dural instead. The oil pump drive was the tricky part, but I managed to incorporate that in with the drive for the magneto. No pics, but you might be able to gleam something from the pic that accompanied the e-bay listing. I used the standard CB750 oil pump bolted to a block of aluminium, which in turn was bolted to the housing for the magneto drive such that the gear on the oil pump would engage with side of the pulley driving the magneto.
The original Honda gearbox internals removed from this engine now reside in the engine with the JMR cylinder block.
Eric