Finished in raw form, meaning the drag brake is functional, but untested. Cable housing is taped down instead of using zip ties and cable clamps. Below are pics of the shifter used and where I ended up mounting it without making a new band clamp. The caliper mount puts the load on the seat stay and the two eyelet bolts. The tail that drops below the drop out serves as a bump stop for the QR lever so that I do not need to center the wheel between the rim brake pads.
If it dries up a little today, I will take the thing out for a test run on a short, but steep hill near me. Everything used is from my parts bins except for the disc brake conversion kit. Ditched the steel clamp plate and have a piece of flat aluminum instead, cut away some of the converter that is behind the drop out to make wheel installation possible. Modified a front 160/140 post mount adapter to work in the rear and allow more pad to contact the rotor.
I do not have the correct tools to do precision work, thus good enough became the standard.
Fortunately since I was modifying the post mount adapter, I was able to angle the flat surface where the caliper rests so that it is almost perfectly aligned with the rotor. Unable to use convex/concave spacers for alignment due to rotor size being only 160mm. Would need a 180 or larger to do that and the frame won't clear that size rotor.

Edit: Tested bike in unloaded condition. Works as advertised. Can easily stop the bike with just the drag brake. I do believe once loaded with 20-30 pounds of gear and my fat butt the drag brake will work as expected.