Narrowing a 8 3/4 diff.

I know it doesn't help you, now. And I realize you're doing this in your garage, in the great white North and all. But, the machinist in me, tells me I would have done this (part 1, anyway) differently. I would have chucked up one end of the hsg in a lathe in a four jaw chuck, with a live center/cone in the other end. Then I would have cut rings in the OD of the tube for running a steady rest. Then I'd place the same end in a steady rest, and removed the tailstock. Then I would cut the tailstock tube end off with a parting tool. I think I'd try (if the tube is thick enough)to cut a precision register on the tube end. This will mate with a female register I'd cut in the shortened brg end just removed. The other side would be pretty much a repeat.