I have been using them since my PA1xPro...I agree with all of UD's post. Good advice for those wishing to use them.

At a guess, without actually going and counting, I use a single harmony voice about 75% of the time. Two voices for 24% and three or more for the other 1%.

The harmony is meant to complement the main vocal not drown it out in my view. My rule of thumb is 65% of the main vocal, but like UD, I will from time to time, and gig to gig, alter this on the fly depending on the room, the crowd and ... how I am feeling!!

Sometimes I just turn it off altogether!

Dennis