The reason why this is so complex is IMHO that everybody has different things going on in their body.
I've been taking 300 mg daily for 1,5 years now and still am not back to complete health or Iodine sufficiency. I have been chronically ill for 20 years. I'm very toxic: nickel, mercury, bromide, fluoride, everything has to be flushed out before the Iodine can be fully used by the body to help make everything work better. There's still too much interference.
But probably if you are in relative good health and not too toxic before starting Iodine supplementation, you could do it much faster. You would reach iodine sufficiency much sooner.
Just started on 4 gram a day by the way, thanks to High on Water. So hopefully things will be going faster for me now too.