Our original plan was to descend the SE Face, but we didn't think we had enough daylight left to rappel the notch, climb back up, go over the summit, find the top of the SE face (neither of us have climbed it) and go down it.
One rap (slung block) gets you from the col on the NW ridge into the gully. The gully is loose and dirty, but easy. When snow filled it would be even easier, and faster. I believe this gully is described in Fairley's guide as the standard descent off Joffre. From turning around at the notch, it took 4 hours to get back to the hut.