Home built rack and pinion+ coilover build.

If you mocked that up I would really like to see a picture of it. A few years ago I was looking into a Coil-over conversion using tubular upper and (maybe) lower A arms w/a stock manual steering box for my '65 Valiant and the bolt/washer retainer was suggested at that time.
You might look at www.bobsprofab.com for his upper shock mount brace as a design reference.
Bob