So today was about 78 and sunny so I got to take a ride. The anti-sway bar works perfectly. I am very pleased. The car corners very flat without understeer or oversteer. I would say it's the most neutral Spyder I've ever driven.
So, a big thank you to Carlos G for the original idea and Jim Gilbert for sending me photos of what he built.
Jim, did you heat-treat your bar after the splines were cut? I have the old book "How To Make You Car Handle" and in it they recommend 4130 steel(exactly like you used) but they heat-treat to Rockwell 38-42 after machining. That is the reason I used the old 911 bar and Tig-welded it to my lever arms.