347,
Your problem isn't with the main circuits. As I said in my previous post, a flat spot below 3000 rpm is a symptom of idle circuits not providing enough mixture through transition into the main circuits. Air correctors are for upper end adjustments, changing them will not help your problem. Don't expect Webers to be environmentally friendly at idle, or above, especially with an agressive cam.
I'm attaching a link to the Inglese website that has some useful technical and troubleshooting info. The HP book on Weber induction systems is also a good source of info.
Mike
Weberology 101