I've tried it when singlehanding but so far I'm not convinced.
3) I think on dinghies you really don't want to move around if you don't have to, because you are the ballast. But on bigger boats, moving around isn't as much of a big deal.
My Capri 22, is hardly a dinghy, however the displacement to sail area on it is high enough, that the crew moving around is well felt. The boat depends on crew to balance it for best sailing.
More importantly, Cross sheeting is a necessity when the wind pipes up single handing.