I used an on-line protractor tool, seems my castor angle is 6 degrees more than it would be if the kingpin was perpendicular to the axis between the cross heads.
![[Linked Image]](https://www.tm-img.com/images/2020/12/17/7ECD392A-4A95-4A71-9CCC-03D514BA5D44.jpg)
Not sure how useful it is knowing that, I still need to figure out what’s off, top or bottom, or the grand prize, both!