It seems odd - but - with the flame roaring, I slowly closed the main gas line three, four, and five turns - and it didn't seem to make a bit of difference in the flame.
Until you guys started talking about lowering the main control, I had figured it's really an on/off valve - but I will need to do some more experimenting to see if I can actually regulate the gas flow from the main gas valve or not.
With respect to the PILOT flow, I suspect you're wholly correct in that the flow to the pilot will happen the moment I crack open the main valve and it won't change if I open the main valve all the way or not.