I would highly recommend getting Cliff Ruggles book on Qjets before you go making any drastic changes. You can also check out his forum and ask your question there as well. He is good about answering personally.
As far as vacuum dropping to ZERO, don't worry about that, it is normal for vacuum to drop off when you open the throttle up.
You may also have the incorrect power piston spring installed (by the rebuilder), and it sounds like you may need a lighter spring.
Also when you adjust the secondary air flap spring, release the tension fully, adjust the spring until it touches the pin, then another 1/3 to 1/2 turn, tighten up the set screw.
One other thing, the choke pull-OFF could be releasing too quickly...the new ones are junk and need to be modified (Cliff sells the modified ones)
