Not being argumentative, just discussing here. The reason I think of OD1 as an “input level” and OD2 as saturation is because I did some experimenting not long after I started using mine, and found with OD1 at zero, you got no sound at all, regardless of OD2’s setting, and conversely, you could get a really strong but clean sound with OD1 turned way up and OD2 at zero, that gets dirtier as OD2 is increased. For me, what works well is with both below 6.0 - as I said earlier, OD1 at 4.2 for a strong signal to manipulate, then OD2 at somewhere from 2.0 to 4.8. My most distorted sound with OD2 around 5.0).
With respect to EQ, I found that, at least for tube dist sounds, pushing bass higher than 9 in my rig results in a real tubbiness in the ~180Hz range, where a setting of 9 or even 6 is tighter, and then backing off the mids to around -4 the leaves room for the frequencies below the bass centre frequency to speak. It seemed counterintuitive to get more and fuller bass by dropping the mids, but it seems to work that way for me. It also takes away some nasal mid honk. Treble & presence need to be dropped to balance against that.
Now, all of that may be related to how I’ve been using the ODs, or it may be because I use solid state power amps. It may also be subject to change once I get into a live situation where I’m driving speakers harder than I can at home or playing through an IR of my cabinets, but I was getting compliments the first gig I did with it (it still had the 3.666 at that time though). Even so, even then I tried to match the general frequency response of my other preamps (a Kemper and an ElevenRack), that I know sound killer in a live situation.