Hmmm...I like the special sweeper set, but what about HP Fire for the final move slot? As good as solar beam is, giga drain heals and still functions without sun. Plus, at +2 anything that I'm going to be attacking with giga drain probably won't stand a chance anyway. As for leech seed, the recovery it offers doesn't seem like a necessity. The only major use I could see it having would be to slowly whittle down special walls that check, but don't counter, Venasaur. Blissey and Chansey come to mind, but they can just heal off any damage that inflicts. Finally petal dance is kinda the same as Solarbeam. I was thinking that HP Fire might work well, as it gets a big boost in sun which makes it pretty much equivalent to a STAB attack and hits the steels that sludge bomb and giga drain have trouble taking down.