I'll have to experiment again, but my current settings seem more realistic.
Before, with my previous 600 amp in the loop, I had to have the Denon on -10 to -12 dB's, the 600 on the lowest setting, and the 350's gain at about 3/4 of MAX.
Currently my new 600 is around 7 o'clock and each 350 is about 1/2 way or 12 o'clock. The Denon is on about -2dB currently.
I'll see what happens when I try unplugging the coax line in from the 600. Before my 350's would jump way up in spl.