It could also be carb spit accumulating around the front of the engine and dripping.

Our engines are designed to use a total loss oiling system. That is, the oil is intended to be blown away in the air stream. If some oil did not leak out of the front bearing area of the engine, the bearing would go bad because of lack of lubrication. Of course, an exceptionally loose fit (it happens) between the crankshaft and the crankcase bore can let more than normal amounts of oil leak.

How do you know if it is too much?

Simple. If the engine has normal fuel draw, it is not too much.

Glow engines, being total loss lubricated, are messy. Some mess is to be expected, unlike with gasoline engines.