For whatever reason, Vans doesn't put a pilot hole in the F-902 bulkeads where the blkhd AN fittings for the tank vent lines go. Mark up a spot ~ halfway between rivets tieing the bulkhd to the gear attach web. Used angle drill on the marks and then unibit to enlarge holes for the fittings.
Vent line fitting, right side
Right side fitting from the back (and blurry iPhone zoom)