I would go with 30% all around, much much better than way.
You first want to ask if they are experienced enough to tint over very tight areas, because behind the tail light there is not much space a very thin tool is needed to be used to get behind the area. Some people have no tint where the tail light is and its looks horrible.
Second, the matrix, it varies from shop to shop, my altima was tinted over the matrix with the existing tint. it may peal but mine didnt when i had my car. on my coupe now, the different shop i went to they cut the whole upper portion where tint touches the matrix and covered the matrix/cut out area with black vinyl, it looks very good, stock.
So it all depends on the shops. But i would ask what i just mentioned to you. Which tint are you getting by the way, i would recommend Llumar which is considered to be the best there is