A tig welder was used to take the ends of all tubes in place while it is on the alignment jig. The jig ensures not only that the wheel will be centered and that the set tube will sit straight, it also holes the sides of the bent frame tubes the right spacing apart for the chainline to work out without interference.
The steel bearing brackets are from UDC
, I thought it was pretty awesome that they supply this part for DIY uni frame building. So all I needed for frame materials was a length of off-the-shelf 1/2" DOM material for the sides and 30mm tubing for the seattube.