NHRA Fuel Cells rules

I am thinking about mounting my fuel cell in my car tomorrow and was just looking over the rules real quick and got to thinking. My fuel cell is a 12 gallon unknown brand. It does not have a sump just has two fittings on top one with a standpipe going to the rear of the cell, the other having a "roll over" ball in it. Got to thinking the one fitting with the stand pipe is obviously the suction side and the other one I'd have to figure is the vent? How am I gonna return fuel? I guess run a return fuel pressure regulator would be the easiest way, correct? But mostly I guess I just need reassurance that the one with the check ball is the vent and it is not a vent cap or anything that, when I get it running, will cause a failed tech inspection.