Hey would you be able to explain the differences in the boards you tested? Just curious on why you picked the evo if you liked the heritage so much. On paper it seems like the evo is much softer than the heritage with the sl sitting somewhere in between them.
To answer your question I'd go with the 390 bosses. Tried k2 cinches, cartels and 390's and much prefer the 390's on my new sl. I was looking for a softer all mountain binding as well as don't spend much time in the park. The canted footbeds are a good bonus as well but i'm still testing which angle i like more. Set them to 3.5 yesterday at northstar and they felt pretty good (15 -15 stance).