Trans Fluid capacity

I have a 727 and the deep Mopar Perf. pan installed. I had drained the fluid which wasn't in there long and it may have 100 miles on it. I had drained it because I had to replace the selector shaft seal. I put a gallon of new fluid in it and it is just on the dipstick, so I need more fluid I assume. My question is this. With the stock dipstick how does one know what the right fluid level should be ? I kind of figured that before the shaft seal install that I may have had it over filled, but this seal has slowly seeped before I installed the deep pan. So at this point I'm not sure just how much fluid to put back into it. Any help would be great. Thanks.