Main differences between the Cobra and the Proto is that the former is directional in shape, a touch stiffer (more so for 2013-14), and damper, while the later is a true twin, slightly softer, and more playful.
Differences between 2012-2013 and 2013-14 versions of the Cobra are quite minimal (slight increase in stiffness).
In contrast, more things have changed, including profile and nose/tail rocker, etc.
However, neither of those two decks matches the type of riding that you describe particularly well.