trans gurus

hey you trans guys out there , I just changed the speedometer drive gear seal , about a full qt of fluid drained out , (maybe a hair more) . Do I need to replace that amount , or was my trans over full ? I suspect it just to be trapped fliud back there .
I have an after market trans dipstick and a loose 3500 convertor , have never been sure of the fluid level in it .
Anyone know where the fluid level should be on a sitting still 727 torqueflite / I realize the convertor drainback will affect the level some ---------------thanks , bob