Roger, can't I just do test holes in scrap to see how far inside the cut line to stay and compensate for chain chatter (also adjust the chain properly)?
I would probably have no problem hogging out the bulk of the mortises with my Bosch 1/2" drill and whatever best bits I could afford…except I can't wrap my head around creating a proper clean angle cut for a half dovetail mortise (I think that's the right term) which I thought would be a good idea to use in the sides of the posts mortises where my beams parallel to the trusses will connect lower than the bearing beams.
Let me know if my descriptions make sense. I can post rough drawings I made if I could find the "File Manager" button this websites FAQs says to use for attaching files.