BillP--you are correct that SPs in 1962 Football is driven by the cereal box(es) that players cards appeared on. As documented by Dan Mabey in his Post Cereal Baseball research, the 62 Football is exactly the same. Besides the cereal flavor, the size of the cereal box the cards came on drives the number of each player's cards that is available. Generally a player's card that appeared on a smaller size of a cereal is less available because moms back then would buy the larger more economical boxes of cereal back then, thus more of those boxes were sold than smaller sizes. With most players coming on several different boxes, it is those players who appeared on two of the smaller size boxes of adult flavored (non-sugar) cereals (eg Grape Nuts, Oat Flakes) who are most tough (eg-Dave Baker the toughest SP in the set). All SP players are not equal in terms of total card distribution and is dependent on the cereal flavors and size of box of all their cards.