Here is Dr Clark's recipe for Lugol's 5% solution.
44 gm (1œ ounces) iodine, granular
88 gm (3 ounces) potassium iodide, granular
1 qt of distilled water
Dissolve the potassium Iodide in about a pint of the water.
Then add the Iodine crystals and fill to the qt mark with water.
It takes about 1 day to dissolve completely.
Iodine reacts with metal. Use 1 qt glass container with a plastic cover.