If you're using Groudon, you need a Chlorophyll Sunnybeamer IMO.
Exe
[email protected] Berry
EV: Speed, Sp Att, Sp Def
Nature: Modest (+ Sp Att, - Att)
Solarbeam
Sleep Powder
Stun Spore
Psychic/HP Special
Double powder cos I assume JAA uses Sleep Clause. If you get lucky with the HP, make use of it cos Psychic tends to suck around ubers, with about 75% being of the Psychic type. Exeggutor is fun, or you can use my personal favourite Shiftry:
[email protected] Band/Liechi Berry.
EV: Speed, Sp Att, Att
Nature: +Att, - Sp Def
Solarbeam
Explosion
Shadow Ball
Quick Attack
Doesn't need that much speed cos of the Chlorophyll, so whack a lot into the Att and Sp Att. Explosion is always fun, Shadow Ball cos of the common Psychic type in ubers, and QA is always useful. Hit and run is the order of the day, especially with Choice Band.