The ocean is really no different from you lake back home. Especially if it is a protected bay.
Sometimes an ocean can produce waves that are breaking close to shore, but also then it is just long swells outside the break zone.
I cannot see any reason why a Rio would be any better in Ocean conditions than a P320.
I think the reluctance to recommend the P320 comes from the fact that almost everyone that provides these recommendations
- dont't themselves sail any board longer than 250 cm
- Don't themselves ever sail in non-planing conditions
- Have not tried, nor can comprehend, what a longboard with a dagger can do
A bit pointed, but basically true.
When you get to owning two boards it should probably be a P320 and a largish GO. Or then two 320 to go cruising together with your wife on the Lake (it is MUCH more fun to windsurf with someone else!)