ALDA Baseline

The ADLA (ALDA?) on my 1980 300D was "tuned" by some sort of expert(?) before I inherited vehicle and I think the "tuning" may be causing sysmptoms below...

When accelerating from a stop, if the reves are kept very low, the 300D emits almost no smoke. If accelerating normally, not racing away, 300D emits clouds of dark gray smoke like a smoke screen. 300D runs well at highways speeds and smoothly around town and produces no smoke above 60 MPH. I assume the smoke screen is caused by unburned fuel resulting from too rich a fuel mixture - a fuel mixture richness caused by the ALDA?

I change oil and oil and air filters at prescribed intervals. My question is - How do I establish a baseline for the ADLA so I may try to reduce smoke screen? Seems like turning the screw without knowing where zero is would cause more problems.