Bruce, for what it's worth...
Whitecloud has absolutely no flat-spot anymore. She really lights up from 3200-4000 but no flat spot off idle or in the weird 2300-2700 transition area.
We finally settled on: 60 idle, 140 mains, 200 air-correction with F-11 emulsions and 34 venturis. I'm running right at 14 throughout but at 3500 up hitting high 14's, close to 15, good enough for a town this size!
Jim wanted me to change the air-corrections back to 180 but I'm thinking if it ain't broke, why fix it?
Ain't it great to have a shop and mechanic you can trust?
I feel blessed, I've got 2, Jim Ansite and Pat Downs!