I do not want to oversimplify all of the various things that must happen.
Every model has a different "map" for the various conditions. Your total cold enrichment plus starting enrichment should be more than 24ma (I think). Some models go to a total of 60ma or more. These values must be looked up.
In general there are a couple of comments. The basic adjustment of -2 to -4ma is usually a good enrichment to help during the non feedback time before O2 sensor reacts. BUT, you mention warm idle settings go to -9ma. You state that full load it goes to +4ma. Well full load is a different condition (not closed loop). I see a problem here. First, you should stay around the same correction at most conditions (other than full load). Once closed loop is established, the relative amount of correction should not vary significantly. To me this means more than 3-4ma.
In other words, if the closed loop correction is -2 to -4ma swing at idle,warm, then the correction at 2000rpm unloaded or constantly loaded should be the same. To go to zero or -6 or more would be an indication of a problem. It can get tricky with pressure measurements part of the testing. The difference idle to part load can also be an indicator of vacuum leaks or fuel injector flow problems.
More power to you for trying a testing approach to diagnosis.
Bosch Master, ASE Master, L1
33 years MB technician