Have a Hangar 9 Areti 40 with a Saito 72 up front inverted.

Regarding engine tank location, can I mount the tank right at the exit hole in the firewall or should the tank be physically lower than that? Also, should the tank be inverted or right side up with respect to the engine??????????????

As well, can you tell me the best CG location for this plane???

Glowfuel

Put the tank right were it belongs. As close to the engine as possible. Upright in the plane.

Your engine is inverted, but the carburetor should still be close enough to tank center not to matter.

Without a pump, put the centerline of the tank as close to the center line of the carb as possible.