Fantastic job there, VERY nice.
The idle problem with the new carb might be the throttle plate being off center and hitting the bore before the plate goes shut. If you can see light at the edge of the plate when 'closed' it might be possible to loosen the screws in the throttle shaft holding the plate to center it in the bore. Just loosen the screws and wiggle the shaft until the plate centers, then tighten them. Do not attempt to remove them, they are staked in place and will break before coming out. That is to prevent them falling into the engine.
The accelerator pump may be bad or the float may be low causing the hesitation. The float level can be adjusted higher to reduce the time it takes for fuel to get flowing in the main jet system on acceleration. That delay is the main reason for the accelerator pump. Set to too high and the fuel consumption will skyrocket, the engine may flood easily.
Like I said, very nice. Thanks for sharing your story.
