You know, to be completely honest, I should revise that about my '56's. I may have gotten overly zealous and certainly I have some 6's and maybe above but I'd say most 56's and '57's are 5's w/ no creases. You can judge for yourself if you see some scans of individual cards in my profile album @:
https://www.net54baseball.com/album.php?albumid=1222 . My '58-'62's are way above the '56's. I grew older and stopped putting the Mays' and Mantle's (I was a Brooklyn Dodger fan) on my bike spokes.