I think Trapper would be the best one to ask about iodine dosage. I would say to begin at 50 mg per day and work up to 100 mg or more. In years past, it was not uncommon for doctors to prescribe 50 and even 100 mg per day, and the amount you take would depend on whether you are taking it as a maintenance dose, taking it to address an iodine deficiency or taking it in a therapeutic dose to combat an existing cancer or other condition.
Twenty minutes or so each day in around noon time with plenty of bare skin (watch out for the neighbors! lol) should give you plenty of vitamin D3. For maintenance purposes, I believe 1,000 iu of D3 is a good daily amount. Therapeutic doses should be in the neighborhood of 5,000 to 8,000 iu depending upon weight.