I have never tinkered with an annular carb. I can see how the main circuit behavior will be different with such a booster and should activate sooner and pull more fuel. I'm not sure about the transition circuit itself but perhaps the booster changes the operating vacuum levels (since the transition circuit is driven by vacuum level) under the same conditions (ie downleg pulls 15"hg at 2K but annular pulls 16"hg). An interesting thought to ponder...
