Quality find / post @Jackson he is a total prof type, but that said very easy to listen to and understand.
His theory on the advantages or not of multi blade rotors was interesting and the section on power control to the motors enabling the uses of smaller ESC's; to pick out just two points.
Also that only a thinner, bottom plate works well. What also surprised was that for his arms, a larger bolt, mounting hole is stronger than a small one.