Hi, good hearing that progress is hapenning on your car Paul,
rear disk setups are personal preference, size, calliper etc and what can mate up with what the easiest !
I have gone the Volvo 244 solid front disk for my rears and 1990+ Peugeot 405Mi16 rear callipers, only cause they have handbrake levers, attached to the housing with 'butterfly wing' shaped 10mm bkts welded on (axles out as heat will destroy brgs). i did this arrangement on my mk2 some 10yrs ago and its been very reliable .
Marty