The cool thing about the new Americana neck is that I’ve added some ogees to the side of the fingerboard. The older model did not have this feature. These shapes are unique to the Americana kit; the minstrel kit also has side ogees but they are shaped differently. The ogees line up with certain frets and can be very helpful for the fretless option.
As for the sound difference in 11” vs 12”. I think it could be debated but to me it is subtle.