Engine/Transmission (1998.5 - 2002) Fuel leak help!

[DWest]

There is a T at the back of the motor in the fuel return line that has been leaking. One line comes from the injector pump and the other from the back of the cylinder head. They have a flared fitting with a rubber gromet that has broken down. My question is how tight do you need to go with these fittings. Will it damage them if to tight or do you go as tight as possible? I'd like to take the line from the back of the cylinder head off but it sure looks like a pain to line it back up. DW