Rather than your suggested approach, I would mount the brake plate and shoes in a lathe and turn them to match the internal diameter of your hub. You will probably need to operate the brake partially to achieve this diameter which you can do,very carefully with suitable adjustment of a piece of wire operating the brake arm and secured round something like the brake anchor stud. As trial and error is needed, use a soft wire rather than anything stiff.
Having got the diameter of the shoes correct, fit them to the wheel but before you tighten up the nut which locks the brake plate to the spindle, put the brake on fully. This centralises the shoes on the hub. Tighten up the brake plate nut, then the spindle nuts and go and try the brake out. Just be careful using it for the first time. It may work an awful lot better then you expect.
36 4G, 37 VH, 53 ex ISDT KHA (project), 54 KH(A), Healey 1000/4 (project)
Former Machine Registrar & Archivist, General Secretary and Single Spares Organiser.