Chemical metal is good to fill in Those nasty curb marks.
As for spraying take your time with spraying primer/colour/lacquer. remember thin coats leave 15minutes between each coat, I found 3-6 coats are good (depending on how thin your coats are, thinner the better) Also between your primer to your colour to your lacquer I would leave 3-7 days for them to really harden.
If you want to speed up the process use a heat gun!
Or your girlfriends hair dryer!
Hope this small advice helps, keep me posted
