I will be shooting a documentary, rolling two cameras at the same time, a Canon 5D and a Canon XF305. Any tips for synching these two cameras using Final Cut Pro’s "Multicam" feature? I have a timecode slate on my iPhone. Apparently, it generates it’s own timecode. I also bought the plugin for accepting an external timecode signal via the headphones jack, but I do not have the proper cable. So, I was thinking of slating the beginning of each take using the slate app’s own timecode and sync it up visually.

Any other ideas?