Vitamin C

I've been reviewing the posts regarding vitamin C with Iodine and I'm still at a loss as to what kind is OK or BEST to take to support the iodine? Is ester C acceptable? Most come with bioflavonoids--is that not good? Is regular old ascorbic acid acceptable? There are brands that are derived from NON-gmo corn (for ascorbic acid). Any other suggestions or brands that have worked well for people? What time of day is best to take it? At night with zinc and other supps? I know it's not good to take with the iodine--but maybe an hour or 2 later? Thanks for any input