Dave F thought some folks might like to follow the saga of my troubles getting a reasonable setup for the Harman Kardon AVR 635 to turn the "second zone" on and off.
I was 'upgrading' from a receiver with a simple Speaker A / Speaker B buttons. The extra features on the HK635 to have a completely independent 'zone' makes it difficult to control from the main room, and my Harmony remote couldn't overcome that.