I was trying just use E-Channel to mix this time, so I didn't use the buss compressor at all, no even at room mic. However I mostly use slow attack on the comp so it gives a tight and punchy sound rather than squashy character, as I'm mixing a ballad song. I use fast attack on bass with light gain reduction, it gives more dynamic control.
By the way I the more I mix with the channel comp, the more I get the sound that somewhat similar to those mixes where you can hear the punchy yet slim sound of individual tracks, works very well for busy mix IMO as you hardly can get everything sits together with big sounding compressor.
Anyway, for the buss comp, I mostly use .1 attack and fastest release for the squashy sound, or sometimes I just use .3 attack and .1/.3 release. Depends on how the sound I want, and how well it suits the source too. I rarely mix rock so I might be wrong on the settings...
