99% of the time I drive stick so I do little to nothing about the settings of the auto, I only se D, N and R.
So dun shoot me for these questions . . . . :-)
I have a good friend that moved to the USA from Spain a number of years ago. He was about 32 years old at the time and came to the University of Michigan to get his PhD in Neuroscience and graduated near the top of his class.
We were on a trip somewhere and he volunteered to be our DD and we had to teach him how to drive an automatic transmission equipped car - he had never done it before!
What setting would give the faster acceleration from a stand still ?
They will all be the same. There is no change in engine power available, and first gear is still first gear. With that said - there are some automatics, typically in larger trucks that vary rarely use their first gear unless towing or hauling, and in those cases using a tow/haul mode can save a small amount of time because the computer doesn't have to start in 2nd gear, realize you really want to boogey, change gears down to first, and then go. It will just start in first gear.
When do you guys go to neutral ?
Pretty much never. Most people will only ever use it to go through one of those automatic car washes that pull your car through them. Otherwise it's only there in case for some reason you need to move the car without the engine running. There's no clutch, so that N is the only way to disconnect the driveline from the engine. Which brings us to:
How fast, if at all, would the auto overheat when not driving and keeping it in D ?
It will never overheat from doing this. However, there are still some people (virtually all of them are well into the closing years of their time on earth,) who will still shift to N when at a stop, no matter how short the stop is. They are convinced that it saves wear and tear on the torque converter or something, or can improve fuel economy by letting the engine idle freely. If it does save any fuel, it's not a measurable amount, and the extra wear and tear on the shifting components will far outweigh any potential fuel savings. Of course, to be completely fair, I have yet to hear of a trans failing because the owner shifted into N too often.