Hawk, your H/K volume indicatorn (like my H/K and many other receivers) is calibrated in decibels (dB). For your purposes, you can assume that "0 dB" on the H/K readout is at or approaching the maximum output of the amplifier, so avoida that level and keep your playback levels to a max of -10 dB. My H/K's settings are very similar to yours. Loud movie playback is a -15 db. Music in DD 5.1 or DPLII is around =20 to -25 dB. The latter will vary depending on how "hot" the CD or source recorded level is, which also affects clipping.
There are no accessory clipping indicators, and the complexity of the music will also affect clipping, so it's impossible to determine an exact clipping point. Just stay away from the 0 dB point on the H/K and you'll be fine.
Regards,
Alan
