The six pack is not the greatest place to begin your carb tuning experiance. Also, stabbing the throttle in neutral is not the best way to determine the status of the tune. Why don't you take it for a ride? What is your neutral and in gear idle rpm?

Based on what you've said and reading probably a little more into it, these are my recommendations for starters:

1) Make sure you don't have a vacuum leak.
2) Set the floats as they are designed to be set, at the bottom of the sight hole.
3)Adjust the outboard carb idle mixture screws to 3/4 turn out.
4)Make sure your center carb squirter squirts fuel at the first movement of the throttle.

Try these and report back.