Most hold between 6 and 10, deep pan, no cooler, and an 8 inch converter 6 to 7.
No as far as what fluid to use. That is a good question. I personally use NAPA type f, but ask 10 people and get 10 different answers. I run large coolers with fans on both my cars, that help with fluid life. I know some cars just dont have the room for a cooler, so in that situation I would run a synthetic fluid.
I see a lot of racing units a year, with a variety of fluids used, from the cheapest thing that can be bought, to hydraulic fluid, to the most expensive, trick fluid on the market. None show anymore wear than the others, now as far as performance goes, only testing will tell you if one fluid is better for you over another.
my rule of thumb is like all fluids, if you change them on a regular basis you should have no problems.