I'm using these J & R driveshafts. If this is the same design as the ones that I bought, they are too large in diameter to pass though the hole in the swinging arm using the normal installation method. After discussions with the owner of J & R I had to take the outer joint off, put that into the hub from the inside, put the rest of the shaft into the diff and reconnect the joint. There's just enough room to do this. The owner said that he originally designed these for Westfields which don't have the hole size problem.
let us know how you get on.