Some interesting observations though...increasing the size of the mains does very little to fix the 2700rpm stumbles (even going up 3 sizes doesn't seem to make much difference). Going richer on the 'tube helps a little but not a lot. What really seems to fix the stumbles is jacking up the idle jet size, but according to the wideband, the idle jet has a pretty wide ranging effect, and still seems to affect light throttle fuelling even as high as 4000rpm.
I try to tell this to people all the time. They never listen. They go buy the book. PAH!
rpm is not as relevant. Its velocity that matter's more. You can run off the idle till 6 grand and the mains wont come online. Lots of people with hicups need to throw the book out the window. Run a richer idle and don't concern yourself with oh no my idle mixture is only out 1/4 turn.