Thanks. I have the second version of the 16-35, so I'll see if I can find a good second-hand 24 f/1.4L II (which would be less expensive than a new one).
You could rent the 24 for your trip... unless you think you will use it a lot after the trip.
5DS R, 1D X, 7D, Sigma 10-20mm f/4-5.6, 24mm f/1.4L II, 16-35mm f/4L IS, 24-105mm f/4L, 50mm f/1.8, 100mm Macro f/2.8L, 70-200mm f/2.8L IS II, 100-400mm f/4.5-5.6L, 580EX-II flickr