I finally got a warm day with no wind so I could set up my tent to weld the fittings. The fixturing worked great. I tacked the strut fitting to each of the spar fittings and then did each weld. I welded from one edge of the spar fitting, around the end of the strut fitting back the the edge of the spar fitting. It took a while to get the 3/16" strut fitting hot enough to start the weld and then when I got about 1/3 of the way on the second side I really slowed down to get enough heat into the weld.
Before welding the first side I used a square to make sure the strut fitting was square to the spar fitting. The fixture plate holds it square in the other plane. They didn't move once I started welding.
They came out great and fit the spars with no distortion from welding so all the little tubes worked to hold the spacing
