I hate to be a killjoy, but CB Mewtwo isn't viable. It has an absolutely horrid physical movepool (Psycho Cut, Low Kick, Stone Edge...? Giga Impact? Earthquake? Poison Jab?) and it just doesn't hit hard enough to merit its use. With Roost in effect, Stone Edge doesn't always even break Great Wall Lugia's Substitute. Plus, it's completely outclassed.
"May the odds be ever in your favor"
"WTF HAX NOOB"
The hills are alive with the sound of PS ladderers.
Come over and help out with the Ubers CCAT