Cheesing QT relies on a d2 engine bug that makes PDR apply to his entire elemental damage after resists, so it depends on your flat PDR.
I did a little bit of testing the other day and you can almost neutralize his damage on a zon with 80% all res and 182 PDR. Every 1% max resist over that should let you drop ~10 PDR or so. Sorcs get extra absorb so you can probably get away with even less (10-20 less, I think).
If you just want to fight him and don't care to cheese the fight, I recommend at least 82% all res and orbing PDR on all your jewelry. That should be enough so you can quickly walk to the other side of the beam without dying if you get in a poor position.