hi.
It depends on which way you put your bulkhead. The question was not asked correctly, but I would answer it by saying to put the gasket on the flare side, not the nut side. It is prefered that you put the flare side facing the water, but minority of people do it opposite way, because of accessibility and setup differences.
I think the usual response is as tight as you can do with your hand. I am a weakling, and have gone an extra 1/8 maybe turn with a wrench with no problem.
The messy way to do it is turn until the dripping stops...