I have a set of (good old fashioned) DOS shareware programs (pulled off the
web somewhere) called Suneedle, used to select the proper, or a close
alternative, SU needle. There is some info on determining the "stations",
or sections on on a carb needle, but I haven't really gotten into it yet,
so I can't vouch for it's capabilities. I am planning on using it next
spring to "dial in" the carbs on the newly rebuilt engine in my TR3. Only
one O2 sensor for me though.
The one section I did check out, was used in selecting needles which were
leaner or richer at a specific section of the needle. That worked well.
Sound like what you might need after you figure out how to tell where the
needle is during operation.
Let me know if you want these programs. It's less than a 500k bytes. I
think they will provide some insight into deterimining which needle
sections are being used too. The readme.txt talks about an upgrade, but I
never pursued it.
One condition, though. If these programs work for you, you've got to help
me run through it next year, if I have problems.