Already own that book.... and many more.
I think the first one I make from scratch will be a 1878 Borchardt or a 1885 High Wall.
What I’d like to find is the right sized shaper to do the interior corners and outside flats. Shapers leave a nice, clean surface finish from their cut, unlike mill cuts.
I ground a shaper cutter to cut the block mortise on a falling block I made. The shop had an old shaper but it was too worn out and used up, so I held the tool in a Bridgeport, locked the spindle, and used the quill to shove it down to clean out the corners and smooth the walls. It worked, but it isn’t for high production.
The outside mill cuts were easy enough to clean up with filing and sanding and polishing.
de Haas gets around the whole mortise with his vault locks and chicopees using round holes or flat plates. Both work, I have discovered.