Hello, I'd stick to a soft microcrystalline wax at about 5-6% and petrolatum anywhere from 10-30% depending on how "Soft" you want the wax to be. Softer will give a better fragrance throw when not yet burning (Cold throw) but it can also melt easier when you don't want it to - like in a parked car on a sunny day. The Sasol 3456 is a good wax with a low oil content. The oil content is a big contributor to soot. Unfortunately, the petrolatum also brings oil content to the mixture. If you are OK with vegetable materials, partially hydrogenated soy or palm oil can replace the petrolatum and help to reduce soot. Good luck. Todd