For quantity I would monitor the amount you use per person per week. for example toilet paper...Enlist your families help and have them only use one bathroom for a week. Count how much paper you use and divide by amount of people. Reason I say this, is during an emergency will others come to you. I know my parents in law would come to me.
So if it comes to 1/2 a roll per person per week x by 52 equals 26.
26 times # of people you expect and that would give you your answer.