fiberglass hood re-paint

I agree, hopefully it's not too bad. If the cracks are small it's probably not a prob but if they are deep, as in through the gel coat, then you will have to sand a bit more and use a good sealer afterwards. I'd be very careful with your DA because once you're through the paint it can sand deep very easily, making quite a bit more work for yourself.
I did speak to my buddy today and he agreed. Sand the paint off but try not to go through the gel coat if you don't need to.