As screenman said, you need proper training. My initial impression is that you need to polish the pit to take away the grey look and polish it to be a "near glass" finish which is possible with the products offered on the market nowadays. The fact that you are posting here gives some credence to your intent. But in all honesty, as soon as humanly possible, get some training. Otherwise, you might be considered one of "those guys" who lend discredit to our art and profession by delivering substandard repairs. There are so many out there, and they are ruining this business. Don't be that guy.