with regards to the vehicle the injectors came from, was it a 4.3 or a 5.0/5.7? *Most* calibrations for the TBI 2F's .bins are designed around the flow rate of the 4.3L injectors. If you had 5.0/5.7 injectors the flow rate IIRC is higher, which would cause it to run rich as the computer would expect he flow rate of the 4.3 injectors for the prescribed opening time, where the actual flow rate would be of the higher rate, there fore introducing more fuel for a given period of time... Double check your injector P/N and ask AFI what flow rate they calibrate for and see if your injectors are up to par.
Ideally your BLM should be 128. that means that the computer is not enriching or leaning out the fueling. Some fluctuation is normal, but there are caps: IIRC 90 is the most the computer can lean it out, and IIRC 150 is a rich as it can go, even if the o2 sensor wants more adjustment.
If you have a realtime ALDL link you can watch the BLM fluctuate. I would say a chip that was in good tune for the 2F would need no more than +/-10... This BLM is the inputed to the "learn" function of the computer, so the closer you get it to 128 steady, the less re-learning the computer will have to do if memory is lost.