I want to mix up some semi-gloss black for painting my wheels. I bought a quart of MTK9300 Single stage black and M148 flatting Agent. The question is where to start for Semi-gloss? I understand it takes some adjusting to taste but I would like to know about where to start. I checked the p sheets and it doesn't address this. I also would like to know if I need to adjust the amount of hardener?