I cut four equal lengths of 1″ EMT conduit and then cut and ground fishmouth cutouts into the ends to ensure a flush 90-degree joint. [Hint: use a fishmouth template. Google it.]
Pictured below are the homemade steering tubes welded up.
Pictured below are the head tubes welded to the cross members.
Cross members are then mounted at 90-degrees to the Beast’s middle head tube. Alignment is critical here.