Then why is there a "v" in the calculations and in your diagrams?
The speed of the light source has no bearing on anything except maybe to determine its location at the time it emits a flash which means you could analyze your scenario with the location of the light source as a variable instead of the way you are doing it, correct? Then instead of something special happening at v/c=0.618, it would happen at some position of the light source, correct? And then you could tell us what that location is and you could show us what the something special is, correct? Why don't you do that?