I think if you used a flat plate for your caliper bracket, somewhere between 10-12mm thick, your life would be a lot easier. The cantilever and those spacers make me nervous.
No doubt it could have been done a different way. However the setup is rigid, the caliper brackets I used incorporate curved sections which give it strength even with the sections I have removed.
Either way I'll report back when it (if) the car runs and I have tested them.