Quick update. i’ve got board lay out complete and parts on order for the second proto board. I may start the etching process today. This promises to be one of the most tricky two sided boards that I have tried to etch at home. When etching boards at home I try to keep them to a one sided design, but connecting the 20 pin header basically is forcing a two sided design. Also starting to work out interface/Disk II protocol. It looks like ADT will be used as a starting point for the interface.