I applaud your efforts, if it is of value here is the procedure for setting co:
1. Disconnect O2 sensor at plug under vehicle. Observe voltmeter reading ( reference does not say where the VM is connected to ) needle should be steady. mark with tape on face of dial, this is the 50% duty cycle reading.
2. Reconnect O2 sensor. The needle should vibrate and should be centered around tape mark on VM ( 50% =/- 10%) if not THEN adjustmetn is nessary
3. Remove plug from mixture control unit. Insert 3mm. allen had wrench and adjust A/F mixture screw by pushing down until the srping loaded adjuster engages with the adjustment screw in theair flow sensor arm. Pushing down on the adjuster will alter the A/F reading somewhat so after each adjustment , disengage adjuster and rev the engine slightly to allow the sensor plate to normalize before checking meter reading)
4.Adjust until the needle is centered around the tape mark on thhe VM dial. ( 50%)
5.remove test equipment and replace the plug.
I hope this helps.