[AndrewJ]

Welcome to ecomodder Harry!

I don't have any instrumentation on my car, but you sound like you've got a pretty good idea of the setup. The current FE, average FE and such are what I'd want to be looking at.

The basic idea should be to keep your current FE as far above the average FE as long as you can, and minimize the time spent below average FE.

As for accelerating, it is allegedly more efficient to accelerate at a certian RPM range at close to WOT. The specific RPM you're shooting for, however, varies from car to car.
So if you'd like to find out what that is, look for your car's BSFC (brake specific fuel consumption) chart. Unfortunately BSFC charts are notoriously hard to find, even with Googles help.