Here's where I'll list all of the things I've done in the Driveline genre. I'll start with the current projects and transition the older stuff as time allows.
So the first order of business was to straighten my wobbly just-get-it-on-the-trailer rear driveshaft that I'd been DRIVING on for a year. The idea was to cut it most of the way around, then with the tires elevated put it in low range and let the engine spin the driveshaft so I can mark where the high spot is. NO, DO NOT get under the vehicle. I used a piece of chalk taped on the end of a broom so I could reach in there. It worked great ... until I pushed on the brake and the driveshaft ripped in two. On to plan B.
So I found some tube that was almost the right size to slide inside. Then I found some tin that was just right to slide inside and shim it all the way around. This is only slightly more scientific, and it came out OK but I still need a professionally built one soon. But it's OK for trail rides and better than what I had.