The drive shafts are the same size, but the CV joint (part of the hub) is different.
Take a look at a site like mini spares or mini mania (mini mania has blown up diagrams) to see all the bits / part numbers, then when you have seen the picys you should know what you need and what you already have.
My set up uses the back plates of the donors rear drums, the centres wer made biger, and were fitted onto a pair of front hubs which were drum ones, the origanal spaced rear drums are also used but you need to move the bolts from the old rear hubs too as the front ones wouldn't leave enought to hold the wheels on.
The cv joints on the original donors disk hubs can be knocked off the end of the drive shaft by following the process desctibed in the haynes manual, but you do need to hit them very hard!!! then you can put the cv joint from the drum hubs on them.
Simon