I guess I'm taking the loop out!!You should not run that loop!!!!!!
I have been down this road many times.
The loop will cause a lock.
If the loop gets fuel spilled into it it will cause a liquid lock. And the tank will not vent correctly.
this has been proved and seen by me in marine applications.
It will work correctly in a role over, as it would without the loop.
Splash fuel into that loop and you have closed the vent. The fuel pump vacuum can not over come the lock.
The vent must pass air freely.
Be warned.
Al