I'm guessing three quarts should do it... ??
I burned through a quart on my front bumper, body kits bits and whatnot. But then, I also probably went a little on the thick side.
As for paint, why go cheap ? If you're gonna put the time and trouble to paint it yourself (and save tons from taking it to a shop), might as well splurge on some good stuff. That's just my opinon.