Does the carb have power valves in it? If it does make sure the throttle linkage is adjusted so it is on the idle circuit only and not up on the transition circuit when idling You may need to adjust the idle screws in so it has from 1/8 to 3/4 turn out from bottom with the linkaged on the idle circuits only on all the idle screws The jet sizes should not influence the idle air fuel ratio There are four or five different circuits in both the primary and secondary parts of the carbs. depending on if it has both four corner idle and power valves in both ends of the carb.
Good luck. let us know what you find and do, that will help others on here later