I have 4.1 degrees caster with no binding and the bolts came out with no jamming. I just took them out about a month ago when I swapped springs from front to back. As I add more caster, I also have to add more length to the lca to keep camber, so that may be whats keeping mine from jamming? I'm not trying to says its a great design or a bad design, just saying it seems to work with my setup at this point without issue. Is that why these other arms he makes have forward heims also?
https://technotoytuning.com/nissan/240z/gtx2-front-lower-control-arms-and-tc-rods-datsun-240z-260z-and-280z