How much does 1 jet size affect A/F?

I'm reading through the PDF you mentioned, interesting stuff.
I'll try the method you mentioned "disconnected plunger" tomorrow and see what it does.

Quick question, and I might be over-thinking this, but could it be possible that at cruise (20" vacuum) I'm actually running off the idle circuit of the carb (which at idle is set at around 13 A/F) and when I move into part-throttle (11"-15" of vacuum) it opens up the primary throttle blades and goes lean since I've leaned out the cruise step of the rod?

I'd set the idle mixture screws for best vacuum and best idle RPM when I sorted out the timing (last year). Is A/F 13 too rich for Idle or about right?