You should not need high dosage. Powder or crystal is OK. Actually orange, lemon, or bell pepper should be OK too. The reason you should keep it about an hour away from iodine, is because it will transform that Iodine into iodide. Iodide is good for you; but you are probably on the Iodine therapy and using Lugol's for both the Iodine and potassium iodide. Each is good for you in its own way.
You just want to get to the point where your gums are recovering.