@LI-Rick, thank you for your suggestion. Because I have drilled out the splines on one side of my nice double u-joint, it wouldn't grip the 5/8"-36 spline shaft. Also, I think the whole assembly would be too long.
When I first built my car I wanted the steering wheel farther from the dash so I did the spacer and two rag joints. It was a bit sloppy. So I replaced one of the rag disks with a Delrin disk. I have the spacer and Delrin disk available if anyone wants to move their steering wheel. It may be necessary to also lengthen the steering tube.
@DannyP, 16mm and 5/8" may be close but my 5/8" u-joint with 36 splines wouldn't fit over the 16mm 60 spline rack shaft. The 36 splines reduce the opening in the u-joint.