The OP looks good, but I'd like to see the fourth moveslot be Rest / Synthesis, with Sleep Powder and Toxic Spikes mentioned in AC. So it should look like this:
[SET]
name: Weather Support
move1: Rain Dance / Sunny Day
move2: Leaf Storm / Grass Knot
move3: Sludge Bomb / Weather Ball
move4: Rest / Synthesis
item: Damp Rock / Heat Rock
ability: Natural Cure
nature: Timid
evs: 4 HP / 252 SpA / 252 Spe
Notice that ability goes next to item, not at the end ;) As soon as these changes are made (remember to implement them in the OP, not in isolated posts), I'll approve this set.