dish painting

Is spray painting matt grey undercoat car spray paint the best option for preserving a dish after removing slight bits of rust or is another paint better?

Just trying to repair any further rust really and prefer to spray. I presume most spray cans do state if ther is lead in them or not?

after rubbing down with wire brush all rust is right on the edges of the dish mainly surface rust not too deep. Got this dish free (again no manufacturer or alike) and the reason i want to experiment as measuring across horizontally this measures 98.5cm as apposed to the 1m I purchased 10 years ago which only measures 88cm. Is it worth a try to spray as I don't want to waste time or money especially if it decays quickly. No rust at all on face of dish. Any opinions great . If this post is boring I apologise. Just like to experiment once in a while. Especially with a freebie.
Cheers. But will this rust on the edge decrement the gain and therefor make it a pointless task?