Jetting and timing question

The idle rpm is probably too high. Everyone says 'idle' but its almost meaningless without knowing the RPM.
Depending on the damper and pointer, only having 15* marked is common. Some engines less.
If the damper is a stock mopar diameter, buy a timing tape or two and stick it on.

As far as the large jets, with a Carter design the jet is the wide open throttle enriched condition. The jet + rod combination is the restriction on the main system. So together they effect AFR when cruising at 50, 60 or 65 mph or more. Exactly when they take over from the low speed system you'll find by systematic testing.