2002 A/T fluid level

Recently changed the filter and what little bit of fluid that can be replaced on these trannies without a transfusion machine. See my previous post "2002 A/T fluid change" for the long version. Added more fluid today because it was taking a few seconds to engage into gear after warming up. My question is: when adding fluid thru the drain plug with the pump, engine running, in PARK, after it has warmed up, how do you know when there is enough fluid in the pan? With engine running, I get a little fluid out all the time, but not a continuous flow at all. Should I add fluid till there is a continuous flow and let it drain till it dribbles like it is now? I've added 2 qts to it and still don't have a good feeling about how much is in there.