If you're after the wiring diagram, there is an early version in post #37 (page 4 for me). It needs some updates though - most notably it needs 2k resistors on the enable + lines else it's a good way to blow the EM806, and it doesn't have the UC300 disabling the drives through the OSSD because this is new for me and still needs testing.

My plan is to update the diagram and post soon :)