If it's leaking out the tailshaft, you either have a leaky seal . . . or, you don't have a driveshaft yoke installed.

A completely dry 700r4 normally takes about 11 quarts, depending on whether or not you have a cooler.

I pulled this from the 4th Gear Inc. website.

The total fluid capacity is approximately 11.5 quarts depending on cooler sizes. The filler tube and dipstick provided will give you an accurate fluid level reading. Put no less than 4 quarts of fluid in the transmission BEFORE starting the engine. Upon start-up immediately add the rest of the fluid (with one already in the converter add 6 more quarts). A FINAL fluid check should take place only after the transmission has been cycled through all four speeds several times and is at operating temperature.