B&K surround model AVR-507

Hello, newbie here, Thanks for having me.
I bought this piece in 2003-5 As a replacement for my Carver pre-amp/Yamaha add on surround sound unit and amps
for the tv/den and sadly never got to it.. I know I know allot of money to have sit, anyways life happens..
So, now I'm try'n to hook this baby up and have it mostly set up. but have a few questions, anyone well versed in the b&k line?
issues if you can call them that..
1) set up menu (on t.v.) got the basic settings down.. but the input settings has a DB level setting is this like a variable line level "gain" or a volume preset for that "source" the manual list it as a tool to level out the volume so when switching from one source to another the volume is about the same, this setting has a -6db to +6db range is there any harm moving to a lower setting or higher setting than zero, I'd think the - settings would be like a preamp limiter that takes some depth/headroom away or isn't totally different, and going to the + set of the range is there and harm sound degrading to doing this, I remember on my old 3rd octive eq(still in use for recording cassettes to cd and vcr to dvd) upping the output level overdrove the preamp input and not advised.. this 507 is plenty loud so the line input gain isn't needed so much for volume, but don't want to degrade the sound by setting the db input range +or- if it is an issue in this regard..
2)the component video inputs do they only work with either the optical digital audio and the rca analog audio and not the coax digital audio? can't find it in the manual other than not to use both optical and coax with the "same" source. I ask because when in set up I used component in#1 for the cable box and the coax digital audio input for the "tv" source selector and I get video(picture) but no sound and no sound from any source until I disconnect the coax audio and reset the eeprom memory to factory settings then get sound .
the cable box has optical audio that I can use with the "sat" input selector input with the component input #1 just a matter of settings in the input menu,
but not sure if the way I have the cable box hooked to the t.v if it's back feeding from one output on the cable box into the other..
I have the s video out of the cable box going straight to the tv.so the B&K doesn't need to be on all the time as the wife only likes the tv speakers when watching tv that isn't movies.. and the cable box component out into the B&K component input #1 set for the tv selector input.
try'n to leave the SAT input open for my either my desktop p/c with pro audio board, if I can if not i'll figure that out later.. **no the plasma 42"(2002) doesn't have an hdmi input**
3) the remote model SR10.1 I have the c/d program disc and while waiting on an ubs to serial adaptor I played around in the software set up and was lost, no idea where to start with programing it, never mind the "micro's" you can set up for one button commands..
Thanks for your Time.