The ratio is 1-2%. One ounce is 591 drops, so you are close to 2% with 5 drops. If it is hot out, you will have ~5-10min of time to use it. If you need more time than that, then use 3 drops.I'm about to do some gel coat repairs. Is it ok to add 5 drops of hardener to half an ounce of tinted gel coat? I'm concerned that the tinted gel coat will change color as it cures. And when we talk about an ounce of gel coat we are talking volume, right?