Nothing Is Too Good for My Cats,so All Their Food

Nothing is too good for my cats,so all their food is custom made at Catastic,who operates a specialty organic food mill in an adjacent state.We need 500 pounds of food per year,distributed evenly throughout the year.It costs $20 shipping and handling to place and receive an order for this delicious food.The cats are fed only on week days,so the 500 pounds per year translates to 2 pounds per day (we go out to restaurants on the weekends).Of course,my cats don't always eat exactly 2 pounds per day,their demand could more precisely be described as an average of 2 pounds and a standard deviation of 0.3 pounds per day.It takes ten days on average to receive an order for food once I place it.It costs $35 to hold a pound of food in inventory for a year and the food costs $850 per pound.It's expensive,yes,but again,nothing is too good for my cats.
-What amount should I order and when should I order it if I want only a 1% chance of running out of food for my babies?