Ive already posted this to someone in Adelaide but forgot to post it here.
The easiest and cheapest and simplest.

The early ge PBR sigma calipers and brackets with 3 (or two think?) redrilled holes to allow the calipers to miss the tie rods by angling away from them works well (otherwise the bracket bolts straight on all the caliper bracket holes match up but tie rods get in the way if you get what I mean) and instead of using the early 120y 218mm or the 1200 212mm disks I used the same early sigma 228mm solid rotor (that sigma weighs about 1200kg so even though solid they handle 610kgs better:) with the inner circumference lathed by 2mm will slide onto 1200 coupe hubs which bolt up straight on.
No brackets to be made just change the master cylinder to the 120y or 1200 coupe one and presto. For power assistance you can try a Pbr off line booster from an early valiant but sorry guys cant remember the part no.
Stops on a dime and hopefully this make some people change their minds bout saving all drum braking original lightweight b10s ;)

Still love to see how to fit Stevos mazda brakes on mine.