Yes. & Highway cruising too.
Depends on the distributor and the engine. In general no. Use vacuum advance to compensate for the increased time for combustion with leaner, less dense mixtures in the cylinder. Strong idle calls for somewhat richer mixture than when cruising.
Depends on how quickly the advance comes in. Big difference if its 41* at 2800 rpm, than if its at 3800 rpm. I don't know how your set up may vary but the older Direct Connection guidelines will give you a reference point.
