I usually give tentacle units to all cameras for timecode (if the cameras don't have it). I run a SD633 with a wireless lav on the presenter and then also a wireless boom. In post everything should then sync up nicely with timecode in post. I must add this is for very small documentaries just usually interviewing 1-2 people at a time with 1 the camera s following 1 presenter. If I had more money I would add some kind of MS system in my boom to also cover ambience in a more professional manner.