The only thing that I can think of, ocean to ocean or sea to shining sea, is that the combination of prevailing winds versus the local area's directions in the currents and the proximity to land and its effects . But anyone that has been on the ocean(s) much knows that while average may exist, it's never average! I'd ignore the sea to sea differences for the most part.
And if old memory serves, I believe Renn suggested that the 18' to 22' lengths work best in Kachemak Bay, due to the type of chop common in that area. But again ... it's a big world.
bd