AVS 650 hesitation

No it indicates too much of the fuel at idle is coming from someplace other than the idle discharge ports.
Main Jets have practically nothing to do with idle.

A Carter idle design is different than a Holley only in that it has a second bleed and second restriction.
My guess is what AJ has already said, the throttle blade position is too far open at idle. Too much fuel is coming through the transfer ports.

Mopar offered a great intro to the carbs systems. May 1966 is a good one to start with Master Technician Service Conference - Chrysler's Training for Mechanics
There's another version a couple years later that touches on emissions and Holleys. Also good.

1. Check fuel level in bowl.
2. Adjusting the idle mixture is going to require repeating steps as each change effects rpm which in turn can effect vacuum which effects mixture.
a. Timing
Measure timing at lowest rpm it will run, then measure what rpm it starts to advance. If the timing is changing with rpm at idle speeds, it makes the rest of the tuning more difficult. In other words it could be 12 at 650 but 10 BTC at 600 rpm.

b. Idle mix
Do not use highest vacuum in neutral as the final determinant. It will result in the mixture too lean for the load with the transmission engaged. The engine is only a making a few horsepower at these rpms. Just engaging the transmission increases the load signifcantly relative to the maximium power that can made at these rpms. See the '66 Carburetor fundementals.

Richen the idle mix screws, then reduce the throttle opening. Readjust the mix screws for strongest idle. Check by placing in gear with foot on the brake. Looking for the least drop in vac and rpm. Use which ever is the easier to read/work with.
Repeat as needed.
If the rpm is dropping off after said attempts, then add a couple of degrees to the initial timing.
This assumes a PCV valve is already being used. If not, then that is the way to bleed more air in and allow the reduction of the throttle opening at idle.

Once the throttle position is more ideal, then the off-idle throttle will respond more as it should.