I had a couple of conversations with Phil Thomas. He said that Cayce had recommended the detoxified Iodine in many (as much as a third) of his readings. What was interesting is that Iodine when added to herbal formulas increased their efficacy. Thomas said that the famous Hoxey anti-cancer formula was borrowed from a Cayce reading and that the addition of the Iodine is what made it so much more powerful.
As for dosages I find that muscle testing is a good way to determine doasge.
Also Thomas greatly disagrees with the formula used by Heritage to produce the iodine supplement called Atomidine. He says they have the formula wrong and that the product is harmful to the body. I realize that he is making a competing product. When I spoke with him he indicatd he had pointed this out to Heritage directly even referencing the Cayce readings . My understanding is that he is familiar with every single one of the readings so has researched the materials extensively.