"4. For the 1/3rd of people (including myself) who experience no subjective response to Iodine supplementation, AND who start out with no significant fatigue or other difficulty, I think that it is likely that they are genetically well-adapted to a low intake of iodine, and high levels of supplementation are not necessary;"
I agree with you T, as I experienced myself no or little reaction to Iodine until I exceeded 60 mg.
Also in my boys,
Today, if they are off Iodine for 3 weeks, one month; - I see some issues make a comeback. Weaker than it was (like trouble with math), but still.