Have you come up with a way to adjust the pilot screws "in situ" yet? Might as well eliminate that possibility (low speed/idle jet too lean) from the picture.
If you adjust the idle screw, the one that raises/lowers idle speed, how high do the rpms have to be before the "lumpy" idle goes away?
"During times of universal deceit, telling the truth becomes a revolutionary act." ~ George Orwell
1995 1500 Aspencade named "Cochise"
1985 1200 Aspencade named "Tatanka"
IDMWT club #18