Personally I would not even try it with hand held aerosol clear, to much to go wrong. And if you mess it up its going to be a bugger to put right.
Take it to your local auto bodyshop and get a price. It may cost more but the end result will be worth it.

What are some of the thing that can go wrong using spray packs.

I dont think ill bother with an auto repair shop, i would rather just re mylar.

Ian