I did mine like that. I have two in each tank, front and rear. They route up to the top of the turtle deck, where they poke through into the air stream. There are actually two vent bumps on the turtle deck one at about 11 O'Clock, the other at about 1 O'clock where the vents protrude. I put the rear vents on the left bump, and the front vents on the right bump. I separated them in case of a bird strike, or something plugs up one of the bumps, I don't loose both vents to a tank.
I'll be adding two more vents (probably put a bump in the center). These will be for my sump tank. (left and right side of the sump tank).
I'll get a photo up on my web site this week as I'm starting the vents for the sump.
The vents not only "vent" but also serve to pressurize the fuel tank.
Waiter