There are several options for getting around this problem. First off, if the engine is brand new, it's best to pull it out and bench run a few tanks of fuel through it, (engine upright), to break it in so you can get the needles set correctly. Then invert the engine on the bench and set up the fuel tank level to match the plane. Run the engine and re-adjust the needle settings. Clamp the fuel supply to the engine while filling the tank and don't remove the clamp until you are ready to start the engine. You might find that after all of this the engine will run fine inverted with the high fuel tank. As mentioned above, be sure to clamp the fuel line to the carb after landing to stop the siphon. Do NOT prime the engine in this set-up and an electric starter is usually needed to get the engine running quickly as soon as the clamp is removed from the fuel line. A Cline regulator is another option for this problem if all else fails.