I think the longest I was in a booth sucking cock through a glory hole was probably 6 or 7 hours- back in the early 90s I used to go to the booths on 8th ave and 35th street and they were always crowded with hot black guys who were happy to feed me their loads for a few dollars. I probably went there three times a week at one point and I definitely spent basically an entire night in there at least once. I have also spent plenty of time in the booths at rainbow and harmony in Chelsea since I live so close.
In my hay day I was more partial to the theaters and would routinely go to the Prince theater on the west side highway, get myself settled in one of the bathroom stalls and blow every black and brown dick that came through the door.