[MichaelBick]

I know a lot of experienced sheet metal teams use very thin sheet(.060" thick) for their drives. However, if this is your first experience with sheet I would recommend using something thicker(like .090" sheet). A pocketed sheet drive is going to be plenty light already, and you don't want to risk a drive breaking in the middle of competition. Once you have more experience you can use thinner sheet. If you have a sponsor with a punch making the parts a circle lightening pattern is going to be preferable. It will make for less time machining and happier sponsors.