Enough of this crap. I found a truck accessories shop in Yuma and they ordered a new all-steel roof rack for me. It arrived the next day. Lou and I installed it while we camped in the RV parking area at the Cocopah Casino, near Somerton, AZ.
After a few hours of swearing and fixing mistakes, ta-dah!
The uprights on the original rack didn't stick up above the cross bars. That's one reason I chose it. I didn't want the uprights casting shadows on the solar panel when the sun was low. Even small shadows can significantly reduce power output. But I'll see how it goes. If it becomes a problem, I could borrow James's angle grinder and shorten the uprights. Argh-argh-argh! Power tools and sparks!