Both boards will be just fine. Especially at your skill level.
You aren't likely to notice the shape, setback or sidecut differences unless you spend all day thinking you are noticing them.
Both boards are very freestyle oriented will do everything you ask them to do.
If you get any sort of real snowfall you'll actually be glad to have the SL as it is a better board than the proto for deeper snow.
Just be happy and enjoy your awesome snowboard.