Setting the idles and fuel/air ratio

Are you having a problem or just asking what the correct way to adjust the idle would be? Your first post states that "everything is great when the headlights are off". Does that mean everything isn't great when you turn them on?

I've never had an A/C before...does it drop the idle a little bit when you turn it on? I would guess it probably does. The headlights should have no noticeable effect. If the idle drops a little bit with the A/C on, then I would adjust the idle with it on because you don't want to have it idling as low as possible and then turn the A/C on and have the car die.

I have mine idling at about 550rpm in gear and 700-750rpm in park. It doesn't get cold enough to snow here and my engine has good vacuum so I try and run it as low as possible year round to save gas. You should be tuning with a vacuum gauge to get the most vacuum as well. You want to be around 20hg on the gauge.