How to tune ThermoQuad secondaries?

I think it's time to give up on this carb. I epoxy'd those two holes in the front of the primary air horn and although it idles a bit better now, it still does the same exact thing when I open the secondaries. I took it out for the umpteenth time to try to tune the air-door tension and again, no matter how tight or loose the spring is set it bogs (just like before) as soon as I tip into the secondaries, then pulls hard for a split second when I let off (followed by a faint puff of black smoke out the tailpipe that I can see in my mirror).