RE: Inverted engine
The biggest problem with an inverted engine is tank height. For some unknown reason, with many ARF's, kits and plans the tanks are designed to fit in the fuselage as if the engine were upright or at best, 90 degrees.
MOST inverted installations require the following:
1. Hogging out (or otherwise modifying) the fuselage former(s) to allow the tank to sit lower in the fuselage. What you want is to have the fuel outlet tube at the plug on the tank at the same height as the spray bar in the carb. If the outlet tube is higher than the spray bar fuel is going to siphon out of the tank and flood the engine.
2. A remote glow ignitor (saves the fingers and hands )
3. More juice to the glow plug. The plug in an inverted set up is a lot more prone to being cooled down by pooling fuel, especially when starting the engine. By using the glow plug connector hooked to a power panel you can minimize the cooling of the fuel by increasing the power to the plug (within reason so you don't burn the plug out ).
These 3 things will solve 99% of the problems with starting an inverted engine.