All of the factual evidence that I've seen shows the short print distribution in states that border Canada west of Pennsylvania.
I have posted this ad before from a May 12 1949 Spokane Washington newspaper. The ad states 6 cards in a pack and that's how many cards were in the packs in the Rosen short print find from Michigan all of the evidence on the first series is 5 cards in a pack.
Leaf Baseball Spokane_Chronicle_Thu__May_12__1949_.jpg