Transmission fluid help?

OK so i need to know how much to fill my transmission...help? Its the automatic in a 1962 Mercury comet 4 door, 160 inline 6.

 

engine running, transmission in park, fill it half a quart at a time until it's at the add mark, then drive around and get it warm, and add a bit at a time till it gets to full. (I'm assuming it has the dipstick and filler tube in it like it should)

it holds about 8 quarts total, but only part of it comes out when you drain the trans, some more will come out when you drain the torque converter