I have both these lenses. To give you a idea of how I use them I quickly selected the past few weddings I've shot. 13,400 images selected. Of these 13,400 photos, the 16-35 f/2.8L II was used 5264 times. The Canon 24mm f/1.4 II was used only 726 times. The other photos spread between many different lenses. I've shot half a million wedding photos to date, and when I reach in my camera bag the 16-35 usually comes out first. Its a little more versatile and really fantastic in most situations. If I was forced to take only one of these lenses with me on a shoot of any kind it would be the 16-35. I would recommend you get the 16-35 for now until you can afford both. If you don't plan on being in very low light frequently then the 16-35 will serve you well! I of course LOVE my 24mm 1.4 and it really comes in handy for that low light stuff! For example taking advantage of that full moon last night with my bride and groom!
This is OFF camera with the 24mm 1.4 ii, no flash, no modeling lights, just moonlight and my flip flop as a mini tri-pod, unedited.