Well, I really fudged this one! First, I changed the servings to feed 20. Then I looked at the ingredient amounts and said, "Nah. Won't be enough." So, the excitement started!
I chopped 3 bunches of green onions small and placed them in a pile in a (approximately) 22 inch by 12 inch baking pan. On that I added 20 slices of turkey bacon chopped small. On that I grated about 2 pounds of cheddar cheese. Over that I sprinkled 2-3 tablespoons of garlic powder. Then I mixed it all together.
I had some homemade freeze-dried mashed potatoes with milk and butter already added that I hadn't tried yet. I decided that now it is time. So, I measured out 3/4 cup per person. I had no idea what it would take to reconstitute the potatoes, and we were having a water shortage (the joys of being our own water company, we have a well... but that's another story) so I added water 1 qt at a time, stirring between additions. In all I believe it was 1 gallon and a qt, but it may have been a little less. Stirred it together and tasted it. Added 3-4 tablespoons of salt. Stirred it up, covered it until tomorrow. Baked it for 1 hr at 350* F. Accolades!