I think I need to go to Carter BBD Skool !
First open the transfer slot on the carb to a tiny square and NO MORE. Then use the timing to adjust the idle where you want it. Don't follow the factory specs for timing, let the engine tell you what it wants. It knows more than a book does.
Then adjust the mixture screw until you get the highest vacuum.
Voila your done.
If you have the transfer slot too far exposed (throttle too far open), you're already into the transition circuit for fuel. Then when you hit the throttle it's adding more fuel and it's too much, which is why you're seeing the hesitation.