Hi Tony, I've had good luck with the Zoom H4 as a backup for audio:

http://www.samsontech.com/products/p...fm?prodID=1901

Also, on the G2, it's a good idea to place a piece of tape on the transmitter to prevent the "mute" switch from being accidentally turned on.

Good luck with your weddings!

With the G2, just wait for the church to power up all their micing systems then use the freq search function on the G2 to look for unused freqs. You won't have an interference problem then.