I'd give it a 1/4 turn and check it in a day or 5
I don't have any #s for you, but I'd think 10-20 foot pounds is enough - which to me is about where you're thinking - 1/4 to 1/2 turn, but only re-torque it once
Basically, with a pair of channel-lock pliers, one hand and some mild resistance. Anymore and you risk cracking glass or squishing out the gasket