Console2 has no effect on two-channel audio that's not being summed- unless you're running something INSIDE it. Then, it passes the dry audio as unaltered as possible, but 'expands' the processing, for instance digital EQ (relevant to mastering). It can have a profound effect on the tone quality of that digital EQ, even in its simplest, least colored form.
However, using it with BussColors3 offers extra power. Since Console2Buss 'decodes' the distortion of BussColors3, the effect is to apply the color of the hardware sim without extra thickening. One of the BussColors3 options is 'tube', which has Manley Massive Passive heritage in its original impulses. This is a way to get a digital EQ that acts like an analog EQ- small adjustments show up, like with analog hardware.
You can also use EQ, which can be used subtly for broad-stroke tone-shaping moves- it maintains lots of transparency when used subtly.
A complete modular Airwindows mastering chain can be long and still incredibly transparent and usable. From the top:
BussColors3 begins the 'inside Console2' section, where Energy adds articulate highs in front of subtle use of ButterComp. The Logic Channel EQ follows, allowing for much detailed EQ work, and then Console2Buss closes the Console2 section.
Desk3 turns up strictly for its overdrive and power supply sections- its High Choke isn't used here. It's making everything slightly more up-front with very small amounts of saturation, and the power supply's tuned to reshape the bass, leaving the attack transient but reining in some of the fullness, again very slightly.
ToVinyl is cutting some stereo bass and highpassing the very bottom to control how it hits ADClip3 (updated with newer product), which is catching the hottest peaks- and then Ditherbox is the last audio component, with unusual dither options.
You'll see at the bottom, two disabled plugins (which are freebies), SlewOnly and SubsOnly, and SPAN, which isn't an Airwindows product at all- it's a Voxengo freebie. These are just as important as the audio-altering plugins. When you use Voxengo SPAN in 'Density Mode', you get a terrific visual display showing the way your audio works the dynamic range available. I had a metering plugin once (only thing that ever drew graphics, modified from a Destroy FX open source plugin) which never worked on Intel Macs, and SPAN more than replaces it, but didn't tell me everything I needed to know.
SlewOnly and SubsOnly fix that. They're not (usually) for use to listen to- they're radical sound altering plugs designed to work with SPAN Density Mode.
If you engage SlewOnly, you get a calibrated version of just the slew rate of your audio- all bright and nothing else. The mix should still be recognizable, without elements blowing up the levels, and the level in Density Mode shouldn't be wildly different in peak energy, though it might be far far weaker most of the time if your mix isn't crazy bright by nature.
If you engage SubsOnly, everything goes away but the lowest bass, stuff you might not even hear on some speakers. This, too, should balance out in Density Mode to be roughly the same dynamic behavior. If you can hear it, it's also worth checking what's happening down there. It should sound like a house party in an adjacent house. It might turn out significantly louder than the normal version, in SPAN, but should not be so nuked that it's nothing but a thunderous rumble.
These (and Silhouette) are now built into Ditherbox as options you can switch the dither to, so you don't need to take up the spaces on the buss with these if you own Ditherbox. If you're using the freebie dithers, it'll look as depicted- option-click a plugin to bypass it or unbypass it.
Most importantly, mastering is nothing without high-resolution monitoring, so don't be misled by the presence of these tools. The mastering chain I've given as an example is capable of great transparency. It won't hurt the sound, but you still have to use it wisely, and that's something I can't program. All I can do is provide the tools, including tools like SlewOnly and SubsOnly to give you sanity checks- the rest is up to you and your ears and monitoring chain. :)