More of a conveinience thing to know how much is in,why not take it out and do a measurement ouside the tank from e to f and see what the guage reads. Ie move arm up and down on the float.
Cost : Little as possible.
Thanks : To those who by their generosity my build has progressed.
Its a handmade sports car not a flaming kit car !!!
If at first you dont succeed,avoid skydiving...
No parachute require to freefall,only if you want to do it twice.