VOX ToneLab Patch Exchange

ok, so i've had the tlse for some time now. im lovin it. it sounds great through my vox nightrain and celestion greens. i used to have th boss ps-5 pitch shifter which allowed me to harmonize with myself. the tonelab also has a pitch shifter, but i cannot, cannot get that clean, nice, precise harmonize that i would like to have. does anyone have any tips on how to accomplish that? thanks!