Ok, here's what I think you might have. The 5% Lugol's that is commonly referred to is 5% elemental iodine and 10% potassium iodide. Your proportion of 1% iodine and 2% potassium iodide is right, and you seem to be correct that it's just weaker. 5% Lugol's is 6.25 mg per drop. Since your solution looks to be 1/5 the concentration, I'd say each drop of your solution should contain 1.25 mg per drop. So, at 12 drops, you're ingesting about 15 mg. The iodine docs usually target 50 mg for a beginning dose, so you'd need 40 drops of your solution. For a sinus infection you might want even more, depending on your tolerance, so I bet you'll soon come up with an easier way to measure these high numbers of drops! :) Best wishes!
I forgot to consider that there can be some variance in size of drops. I assumed an equivalence that may not exist. Even so, after enough experience at higher doses, you'll soon figure out what works for you given your current setup.
I don't recall a problem with Lugol's staining teeth. In fact, some people have used it in their Water Piks. At the same time, I probably wouldn't want to paint my teeth with straight Lugol's! Diluted in water it should be just fine.