I was really damn concerned about the scratches my car accumulated (Black Sapphire). I kinda have given up now... cause at the end of it all, your going to get scratches no matter how you try.
All I do is use foam gun instead of a regular brush and use wool gloves to wash them. Then, I use spray wax or hard wax to protect the car.
I've had the car for a while and tried many different things but kinda ignoring the scratches helps you not to stay stressed ( I mean come on there are better things to do in life) Just sayin!