Its not just the weight of the cloth, it will also take more resin and primer to fill the weave of the cloth.

If you don't mind the weight gain, it will work just fine. I personally do not care for .5 oz cloth, and use 1oz for most applications now, but I am adding extra weight. The more experienced you get with laying cloth, the lighter you can get it, but I remember my first few attempts and they were all heavy.