Good looking plane, except you need some color on it!
You really shouldn't have fuel dripping even on an inverted engine. Your idle/low end sounds a little rich. Most likely it's the regulator, not the idle screw setting. I'd recommend leaning the regulator setting just a little, maybe 1/8th or less at a time. Turn it clock-wise just a shade a see what happens. Give the engine several seconds after you change it to see if it has any effect. If the engine is running well in every other way, don't change the regulator setting very much.
If adjusting the regulator slightly doesn't help, then try leaning the idle setting by turning the idle screw out, CCW, a little. Remember that the idle screw is an air-bleed type, not a needle valve, so it works opposite from a regular needle valve. Turning it out leans the engine, turning it in richens it.
Hope this helps!
David