ouch.
i cleared through psychic gym easily with a gardevoir/kirlia with shadow ball... i dont recall vividly.
these may sound stupid, but...
u can try xspeed, xspedef and bulk up x6 with blaziken
or gyarados with xdef, xspeatk and a dragon dance. have it learn surf/hydro pump.
u can also revive wobuffet like 4 times
dont forget the chesto berry!
never used any xitems before
:)