One bottle should do. PLEASE, keep in mind, it will be MANY THIN coats to get the pearl effect right. DO NOT throw on heavy coats. You will just be pissed off with the paint job when done. You will want to back it with either bright white or race silver (you can get the rattle can version for your backing process)
You will want to back it when you are completely done with the regular paint job.
One can (backing) and one bottle of pearl should be good.