Unfortunatly, I've done it both ways, over backwards and rolled it.
Rolling is more scary and when going over backwards eveything goes into slow motion.
Both times were years ago in my Fathers old Flatacraft.
Took the winscreen off each time but the old Chrysler 35 always started after flipping the RIB over with the painter.
Taking too many chances wave jumping in too smaller boat was the cause.
RIBBED For extra pleasure.
Member of the ebay Blue RIB cover club.
Member of the Bombard 380 Aerotec club