My Austin is a Speedway kit, and I also found the instructions to be pretty lacking. The axle itself wasn't hard to figure out though, so I didn't have too many problems. Did have issues figuring out why they gave me extra bearing races for the hubs, but after I swapped them all was well.
I used my stock spring shackle location in the rear:
My Corvair box is in front of the axle, so my steering is forward:
This was early when I was mocking it up, and had to swap brackets when the steering box wetn forward: