I wanted ergonomic bars so that my hands would not be twisted all the time, and my carpel tunnel syndrome would not hurt.. Note the forward holding position for leaning into the pedals. Weld them right in the jig.
7/8th " OD x .745" ID x .065" wall
with a small piece of 1" OD x .884" x .058" wall over the center of the tube to be clamped.
I had to gouge out a recess in the ply wood for the extreme thickness of the center tube. so that the whole thing would sit flat on the jig for tack welding.