CC, thanks for your reply. Yes, my testing included CCN, CEP, CEL, DCQ, and soon DCP, and DCN. I'm hoping that if I go with the modified carb I can move toward a richer and longer L1 (on the needle). Through 4 progressive modifications I have been moving toward the magic TV#7. I'm at at least a #6.5 right now (about 1/3 mm below #7 cutaway). My slide modifications seem to mainly effect 1/8 - 1/4 throttle with only a very slight effect below 1/8 throttle. The longer L1 seems to help the most below 1/8 but not enough, even with a very lean diameter. I've also tried pilots from 48 down to 38. When I improve the idle to 1/8 throttle problem, I also bring on a serious hesitation or flat spot when I "wick it" (as you say). This sounds insane, but the richer I go on the main, the better my flat spot/hesitation gets. I'm now at a 168 main and my WOT chops are almost perfect. As a matter of fact, my last WOT run had slightly stronger top end just off WOT than at WOT which suggests to me that I need to try a 170 main (69 degrees, 2600', 30% humidity). This is one of the reasons I'm considering the RB mod. I'm way outside what most folks are running, and yet very little smoke or spooge and very powerful.