I've done a 2013 Explorer, a 2012 Veloster, 2006 Crown Vic and the hood of my 2002 Dakota and still have more than half of a 16oz bottle left, like they've said above once the towel loads you use less.
Get the 16oz and make sure you like it, you can always get a gallon later. They are not going to get rid of it anytime soon, it's darn near magic in a bottle.