Vanguard 15 dinghy stuff
First of all, the V15 is nothing like a 470 so lets just not talk about that anymore.
As the last person said, while sailing wing and wing the skipper sits on the leeward side holding out the jib and the crew holds the board and the boom and heels the boat. If the jib is collapsing while your doing this then your sailing too high, head down(its ok if it collapses every once in a while). In light wind conditions you can even sail by the lee a little(be careful). The main actually starts to work as a foil in the opposite direction, it also dumps air onto the jib. The biggest thing to remember is that almost all boats are slugs going dead down. If you can get the boat on a plane, do it(speed kills).