Thanks for the kind words.
This morning I had a good look at the area where the brake plate disk makes contact with the rear of the rear clutch hub and I still had concerns about the brake plate getting hung up on the inside of the hole so I removed the driveshaft, disassembled the clutch, pressed the release bearing back off of the hub and turned the rear face down about another 1/2" in towards the centre in the lathe. Now the inside of the brake plate will easily clear the step in the rear of the clutch hub - had a look at some pictures of my 1050 hub and originally the hub was flat across into the centre (the 1050 and the 1053 rear clutch hub are the same part number according to the parts manuals). This tractor must have been run for some time with no friction material left on the brake plate to wear the rear of the hub as much as it did. Got things back together and reinstalled back in the tractor and called it a night.