Volume levels of surrounds including L/R rear and L/R sides depends upon U..
My preference is to have these set slightly lower than the L/R fronts & center..
Depends upon source material; movies often have little surround information execpt during high action and/or fly-overs..
Muisc can vary depending upon the audio mix..
Here U need to try various settings that suit U.
First run the AVR's auto EQ, than write down the values so U can go back to them if...