My bottle of idophor has the dilution marked on the side, 1 teaspoon per 1 1/2 gallon of water. According to the internet (!) 1 gallon = 124 ounces so . . . 1 1/2 gallons = 186 ounces . . . 1 teaspoon/186 ounces = x teaspoon/24 ounces . . . 0.0054 = x/24 . . . x = 0.13 teaspoons
So, 0.13 teaspoon of idophor for 24 ounces of water - good luck in measuring that! I think it translates to "a very tiny amount".
Also, I've never heard of folks using idophor in a spray bottle before - many use star san in a bottle, I think it may have something to do with how long idophor remains effective after its diluted? I'm not sure . . .