I would try a Salac sweeper, like this one.
Medicham@Salac Berry
EVs: 252 ATK/252 SPD/6 HP
Nature: Adamant (ATK+/SA-)
Endure
Reversal
Rock Slide
Shadow Ball
This can be very effective against teams that don't have T-Tar. Another option, better against T-Tar, would be:
Medicham@Leftovers/CB
EVs: 252 ATK/252 SPD/6 HP
Nature: Jolly (SPD+/SA-)
Hi Jump Kick
Shadow Ball
Rock Slide
HP Bug
The former is the e4 recommended set, but the latter works as well. As for special attacks, the only one Medicham has any business with is Psychic to kill Weezing, or maybe Fire Punch for Skarm/Forry.