Ok... I just think it is a rather overwhelming advantage.
In this position the pitcher's body (shoulders and all) between home and first at a 45 degree angle.
The plate mechanics I could care less... the ability to move to first has been greatly opened up.
Sure MS.. he still has to gain ground... but barely from this set position.
Very small step, very little body movement, etc etc
8.02B says the free foot or stride foot has to be in front of the pitcher's plate. Does this mean in front of the plane of the rubber, or in front of the plate itself?