Good idea Scott. Threaded rod, 4 nuts, 4 washers. Lock everything in place. At the point where I sliced the 1" brace, in the center, it was about 1/8". What I did was to then wedge the sliced brace with a steel chisel,and then check for correct fitment on the fully assembled rear axle/wheel , open up Slice to fit 1/4 inch stock, then weld it up. What the spread is at the rear where the axle slot is, I'll have to loosen up the axle nut and measure it for you, let me know when your ready. But to be honest Scott, I think doing the wedge technique is more accurate and more forgiving.And not that much more work. I would bet that there are variations from swing arm to swing arm. Remember, those two side tubes are over 18" and what are the chances of getting perfectly straight sections from bike to bike? Especially after factory welding. Those side tubes are just butted against the pivot tube, at an angle and welded in place. I don't know how good their jigs are. so what worked for me, may not for you. What happens to the Brace, when you weld it, is that it shrinks over it's length from it turning from a solid to a liquid. difficult to predict. HOT LAVA!!! Be careful because the side tubes flare out from each other, so the axle slots are going to measure narrower at the front then at the rear. It is probably best just to fit it.
Your welder should be able to do it, no prob. Just bring him the wheel assembly and show him how it goes together.
Dan.