Pokemon VGC '10!

[Cshad]

Don't run a mono rain dance team. It's really just a bad idea. Anyone with Weather will screw you up just by switching in, and to be able to use weather by just being there as opposed to having to waste a whole most slot is just such a huge deal. If you lose Kyogre you lose the momentum and all the speed bonuses your Pokemon get as well as Toxicroak's free healing. I suggest running an anti weather pair in the back (Rayquaza/Shedinja work rather well) if you plan on using Kyogre as a lead. Give Kyogre iron ball. You want him to go last. Really, you do. The slowest weather activate-er = the weather used. Ie, the battle begins. Abamosnow starts off against your Kyogre. Hail will be used because Obama over there is slower than you. This will put you at a big disadvantage from the get go. A really big disadvantage, especially since your team is 100 percent reliant on the effects of Drizzle. Switching will cost you dearly and you will probably lose very quickly, which would really really suck. You could also run Metagross/Giritina in the front for some free exploding,and you wont have to be reliant on iron ball if you don't run him as a lead, freeing you up for another item. Be it Scarf/Leftovers/Life Orb/Wacan Berry (Thunder is common~) or whatever. You could also run Palkia (same typing as Kingdra only better in every way except for Swift Swim) in conjunction with Kyogre for a trick room rain dance team (assuming Kyogre still has iron ball). That might be cool. But it's really up to you. Only trying to help~

Also Choice Specs will lock you into whatever attack you use. The extra Power and Double Speed from the rain is worth it though;

http://www.smogon.com/calc/

Use the Damage Calc and figure out what move will hit the opponent the hardest if you're worried about not doing enough damage, since you seem to be worried about Mewtwo still. I think Draco Meteor or a rain boosted STAB Surf will hit him harder than Signal Beam, though.

Also, if you think you're sets are doing well from just playing a few times, well, play longer. The way the laddering works is that you get a special score called CRE as you beat people. Depending on how high your CRE is will also determine who you play against. You will meet competent people at around 1200~ or so CRE. This will give you a good idea on what you need to fix against what you have problems with.

Here are some videos of the battles that have already gone off in Japan and other places;
http://www.youtube.com/watch?v=UvHoA-Q22Tk
It's only one video but will lead you to a whole bunch of other matches off to the side. This should give you a good idea of what to expect~

Again; I suggest looking at these, you don't have to use the exact sets, but its a good starting place and you can figure out a good strategy to use as well as what most people will be running, making it easier to know what to expect and how to deal with it.

http://skarmbliss.com/pokemonanalyses.html