I looked into the all-pro leafs awhile back, and IMO, they should work. The 56" is about right, and the center pin measurements are close, but not dead on. If I remember right, the center pin distance was within an inch or so. I have tried to look up my references for stock Explorer center pin measurements and height measurements, but to no avail. You may be able to use this info for comparison though. As I remember, the yota leafs are MUCH more "curvy" than Ex leafs.
From an All-Pro representative:
Center Pin measurement:
3" = 26"
4" = 26.25"
5" = 26.5"
Height*:
3" = 11.5"
4" = 12.25"
5" = 13"
*height=with leaf on gorund in ^ fashion, the unsprung distance from the ground to the top of the highest leaf