I say get a bunch of 600 grit from home depot and wetsand. Then polish (buff) it up. The 400 is slightly too aggressive for the final sanding. Your car is going to be astounding Phil. I would say go ahead and do your hood since it is not connected to the rest of the car. You will be amazed.
Get some good buffing compound as the aluminium polish is just a tinge rough for paint plus it does not go very far.