Hydroquinone powder (commonly used for photography) is dangerous to use and mix in your own solutions. All of those mixing agents you mentioned also sound harmful to your skin. HQ is a strong chemical substance and unless you are a chemist I strongly discourage you trying to create a homemade concoction. You will damage your skin. I’ve seen many people who have. Sorry but with that in mind, I don’t have any advice on creating a mixture. My best advice is for to go to your doctor and get a prescription for high strength HQ cream if you can afford it. I have one for 12% and it is great for fading scars. It is a controlled substance and mixed in the lab by chemists, dermatologists, and scientists. Quality and safety in your products will get you results.