I've done some syncing of two cameras, and I find it's pretty easy to do with just the normal sound. As long as both cameras "hear" the same thing, I put the primary camera in the main track and the secondary camera in the overlay track. It's best if the primarly camera has the best audio -- the secondary camera can have poorer audio (from farther away, for example) and that is not a problem.
With the tracks loaded as I mention above, trim the secondary camera's track so that you have some room to slide it left/right on the overlay track. You want to line up the sound so that the two overlay perfectly. If you hear any echo or reverberation, move the overlay track a frame or two in one direction. If the sound gets better (less echo), you're going in the right direction. If it gets worse, move the secondary track back to where it was, then slide it another frame or two beyond that point.
When the two tracks are perfectly synced, the sound will have the least amount of echo/reverb. In many cases, it will have no echo at all. At that point, mute the overlay track's audio and you can slice it up to cut between it and the main track.
It took me as long to write this out (5 minutes) as it does to sync up two 10-minute tracks using this method. Hope that helps!