But whatever you do... Tape yourself, and listen critically to the harmonizer. I'm sorry, but I am not a big fan of most of the harmonizers in arrangers, compared to dedicated units, being much cheesier and chipmunk-y than the best hardware units.

Tape yourself, and ask yourself does the effect distract, or add to your singing? It's a cool effect, when you are playing, but often, in the light of a cold, objective listen after the fact, it doesn't sound anywhere NEAR as impressive as when you were actually playing!

JMO....