longboard windsurfing website has more user info on the 380.
A few guys "up the road" who ranted and raved about them bought them and are racing . However a friend of mine raced against 2 them on his equipe II in primarily light airs and found he traled them by small margins , sometimes seconds. This seems to confirm what the longboard website said the 380 is competitive but not overwhelmingly so.
However that being said , the 380 still beat him, and to some that is all that matters for a podium finish.
Yeah after sailing a melges all summer the dreaded 6 to 12 knots killed us. In these winds we managed to get ahead upwind on boats slower then us that we had to correct over at the finish but downwind those same boats made up the time.
As to a windsurf rig leading edge slots, well they increase light but also increase drag.
Aircraft using them use them primarily for takeoff and landing , at these time engine power is on full and angle of attack is also high, very ineffecient but it allows aircraft apparent speed to slow while still flying, wheels hit the groudn power off viola short takeoof and landings. Planes that have these leading edge lift devices deployed continually suffer from lack of speed while cruising , due to drag from these appendages.