You can 'gang' as many adjacent channels as you like for simultaneous adjustment of the recoring level (and also monitor pan and output level), and you can un-gang and re-gang them in different groupings as necessary while recording. So for instance, you can adjust individual levels on each channel, then gang them as pairs and adjust them that way, then gang them all and adjust all channel gains together simultaneously with one knob.
You can record either individual mono files (1,2,3,4,5,6,st) or stereo file pairing adjacent channels (1-2,3-4,5-6,st). The "extra" stereo channel is always written as a stereo file, even if you set the machine to record mono files. It can record either two additional channels via the digital input or a stereo mix of the 6 analog inputs. While in record/pause, you can choose to arm or disarm any combination of channels or pairs of channels within that framework.