Hello,
Don't know if this would be of any help but I have some spare T3 backing plates for sale.
Also have spare T3 hubs (use those in combination with 914 discs and stock T1 calipers) for sale.
Brackets:
http://www.classicvw.co.uk/test/parts.html (NOT mine)
This combo does effect the track on a T1. The hubs need to machined down for usage on a T1.
Van der Jeught Bert,
BELGIUM