fuel mix adjustment

[ssanmor]

Sorry for asking this again, but I have doubts and nobody has noticed a previous posting about this.
I want to adjust the fuel mixture of my 190E 2.3 properly. From some postings here, I must monitor the duty-cycle reading at pin 3 of the X11 connector while adjusting the 3mm allen screw in the fuel distributor.
Should I do this with or without the 02 sensor connected? What value should I look for and at what engine speed?

Thanks!!!