ORIGINAL: Trisquire
On a typical upright engine installation, it's a bit of a challenge getting the tank high enough. If it was me, I would just let the tank peek out the top of the fuselage. Not pretty, but functional.
The alternative: mount the engine horizontal and the carburator will be lowered, then the tank installation will be placed in right height to main needle.
But most generally: Follow the building construction/plan of aircraft where the engine and tank will be placed in right place.
Some time the tank are in the kit of model airplane, and follow instruction where the tank are placed.