One way out of this would be to go back to your machinist and order the kit through him. Then if stuff starts not fitting then it is HIS problem, since he bored it. Sure he’s going to mark the stuff up, but what price your sanity? Regarding choosing parts, if you go that route, not a lot of variety out there. If you were to go to CNH “genuine” parts, they likely dumped the parts out of Reliance boxes and re-boxed them in CNH containers.