Fuel system venting

[mizfitjon]

Hello...I’m trying to plan out how I’ll be doing my fuel tank vent system on my mustang. I have a Ricks efi tank, ridetech fuel cap, and will be ordering II much fabrication vent canister. I need to install a rollover valve and that’s where I get confused. The filler neck in mustangs is the highest point in the fuel system. Meaning if the tank is full there will be fuel up in the filler neck. If I screwed a rollover valve directly into the tank bung (covered in photo with painters tape) it would be pushed shut by fuel trying to entire vent line to height of fuel in filler neck. Could it be screwed into II much canister feed line port as the canister will be mounted up as high as possible? Or for this issue is that what discriminator valves are for?