Joel, I had this issue just today. I had a slight ‘ghost’ audio, but when I bumped the H4N track up a frame, the ghost disappeared. (Why the H4N spike would be one frame off I have no clue.) So my experience is to use the spike to get in the ballpark, and then finalize it by ear. That may be wrong, but it worked for me.
There is a product called ‘Pluraleyes’ that now works for Vegas. It is supposed to be really helpful in situations where you cannot get clap board spikes (such as press conferences), or when you have a lot of different tracks to synch up.
I wonder if Pluraleyes has an issue with the clap board spike being a frame off, or if it overrides the clap board spike based on the rest of the waveforms. I think they have a free trial, if you want to try it.
Norman Willis
http://www.nazareneisrael.org