RE: Inverted OS .46 Floods
When the engine is running the tank is pressurized. Therefore more fuel is provided than what gravity can provide. So tank location is not the problem. The excess fuel that builds in the bottom of the case of an upright engine is just gathering in the head of the inverted engine. A higher idle or on board ignition are your best bet.
Please perform the simple test of inverting the plane and observe the idle characteristics. If the idle is fine then the problem is what I described above. If the idle is not fine then you have other problems.