To return or not to return

[Slyfox]

I was thinking of taking all my stuff and put it on, so my question, where do you put it into the header tank, could I just tee into one of the fuel lines going into the tank or do you go into the vent line up twards the top of the vent where there is no fuel.

I got all the necessary fitting for the engine side, just need to know where to put it into the header tank.