Need help tuning Quickfuel carb

I very much doubt this is a wire problem; because it is related to throttle opening.
If the engine takes WOT without issues, then the entire ignition system is fine, including the plugs, and the wires.
A problem like yours that can be made worse with the throttle valve opening, for me,has always been an A/F issue, Except, except, if the timing was too far advanced for the load. But at Part-Throttle and 2500plus rpm, this is hard to achieve, mine like all I can give her,over 45*.
The A/F issue could have it's source outside the carb, and outside the intake. But I'd be willing to bet,it's AFR.
And I've been wrong many times.
And I won't run an MSD on anything I own.
On a street engine,I don't see the point. Heck I've even run a 292/108 cam @11.3Scr......on,get ready for this; on an Orange box, and to 7200, for about 8 months. Then I swapped the cam out...... but still kept the Orange box for about 3 more years. lol.
I lost a decades-old pick-up and an ancient ballast, but never the ECU. I put that O-box on my brothers van a few years ago, and it's still going.
I tried an E-core coil, triggered by a Jacobs CDI-computer, but that didn't last long; the Jacob's died. And the following system didn't like the E-core. So in 2004 I bolted in an Accell sq-top, and that's been sparking reliably for over 100,000 miles.
Hyup, IMHO, this is a mixture issue. And if I had to guess, which I am now going to do,lol,and assuming all other avenues are exhausted(like the T-port sync),then, I'd guess a plugged main air bleed, or a missing anti-siphon weight in the accelerator pump circuit. If the plugs come out white then the former, if black the latter.
HappyHunting