If I have a popcorn maker that handles 1 1/2 gallons of finished popcorn, how much unpopped corn do I need to make that much? (I.e., what is the conversion from unpopped popcorn to popped popcorn?) I realize that different types make different sized final popped corn, but please give an average! Also, is hulless popping corn any better than the regular hulled varieties? Thanks!