Painting the body with or without the doors on

[California Charlie]

I have future plans to paint a 1931 Slant Window Fordor Sedan and have a couple of questions:

-Is is preferred having the doors on or off when painting the body? Painting the doors separately and re-installing them afterward?

-Is it preferred to have the gas tank on or off when painting the body? Painting the gas tank separately and installing it afterward?

Is there any general information available about painting a Model A Body?

Just looking for a presentable paint job and not one necessarily perfect for judging.

Thanks to all who take the time to answer my questions.