the more oil in the mix, the faster the oil in the engine circulates. In a new engine that is important.
Experiments of Gordon Blair showed that it took 1/2 hour for all the oil in the engine to be replenished. At a 5% oil mix! That is one of the reasons why I believe in "more oil is better"

Dark grey is good for running in. As the engine loosens up, this can be changed to light grey by tweaking the H-needle.