Strut rod and polyurethane bushings issue?? 74 Dart

Hey guys,
I am in the process of rebuilding my entire front suspension. I am using all rubber bushings: however, the MOOG k7068 bushings are currently not available for the strut rods so I am thinking for substituting them with polyurethane. I have read that this will affect the caster come time to align it??? So question is, anyone with knowledge about this or will I be able to use poly bushings??