Steve -
you can visit several of the web sites that offer complete kits. Take a look at what they include in their kits - as many specify how much and what weight of glass is included. In most cases they provide sufficient glass to make sure the buyer doesn't run out - but not so much there is a lot of waste.

I would consider 9 oz. interior glass and 6 oz. exterior glass to be a bit of overkill on a strip built boat unless you are planning to whitewater over rocks and down waterfalls. If you are building a cruising kayak it is my opinion that 4 oz. exterior and 6 oz. interior should provide sufficient strength. Of course, I could be wrong and will defer to others to provide facts to back up such a heavy fabric.