the overflow thing has been discussed here a number of times, it has to do with the colder gas out of an underground tank expanding as it warms up in the truck - and parking on uneven ground - always stop filling as soon as the nozzle kicks off, don't try to top it off unless you're on the road and will be immediately driving enough to run the level down
talk to a shop, it'll depend on the painter, but over spraying the bad area and compounding the edges to feather it in can work fine
Bill
