I really think you have something here that it very important. I have wondered why the fomula for energy of a photon is E=hf. There is no amplitude of the electric or magnetic field that the photon is made of. I concluded that the amplitude of all photons is a constant. I don't have it all figured out yet, but I think with your insights, we can figure out what that amplitude is and why it is that quantity. You can find out why I think that the amplitude of all photons is a constant if you read my article in Medium "What is it that is quantized in Quantum Mechanics." I will subscribe with you and I would really like it if we could get into a dialog. You may have answered the question as to why it is the amplitude what it is. The angular maximum of 90 degrees rotation makes sense to me.