Rambit, definatly get an SPL meter.
Along with D.Rowe I just bought a 950 and am using my receiver as the amp for now.
With my receiver I only trimmed the channels about 2db average.
With the 950 I had to trim them about 9db down to get 75db using the test tones.
I was kind of surprised I had to trim them so much. I have setup many home theaters for friends and never had to go more then 5db from reference before.
Hope this helps.
btw the meter is very easy to use once you try it, also get the analog one not the digital.