[Caprimaniac]

If you disregard the O2- reading on your AFR- meter, what does your plugs look like?

With warm engine: Bottom the throttle to get the engine to stumble, stop , turn off engine and check the plugs.

I'd also checked the plugs at warm idle. 55 idle screws might be on the large side. I have 50's in a 347 with a much hotter cam. (If a little sooty at idle/ low revs your transition gets stumbly when plugs won't fire properly.)

A AFR- meter does not alway show you what it is supposed to. Where and how are the sensor mounted? Have you calibrated the gauge???

Also check your timing curve. Max timing? When?

I guess you should be fine with the F11's. The rest of the jetting sound OK too. Although your 65 pump bypass might, but I think not, cause some trouble while accelerating.

I have 48 IDFs and plugs are light chocolate brown in all kinds of conditions. No obvious stumbles. The jetting are on the list.

There was a guy posting a "How to install & adjust a 44 IDF- setup" here once. I think it was a PDF. I looked for it the other day, but could not find it... Maybe something for you it if someone is able to find it....