Hi Saltgrass,
I don't have the Odyssey, I have the Rift, so I can't give you specific feedback for your HMD. However I might be able to at least tell you what you should expect if things are working correctly.
Firstly, current gen VR devices (even the Odyssey and Vive Pro) are not going to look as sharp as any modern monitor. This is because they are using about the same number of pixels as a typical monitor to represent a MUCH larger angular field of view. (This isn't totally accurate but close enough for getting a basic idea.)
Because of this, you likely will be able to see individual pixels if you go looking for them, as well as the very tiny space between the pixels (this is referred to as 'screen door effect'.)
Despite this, you still shouldn't be having that difficult of a time making out the gauges in the planes. In a plane like the Pitts biplane where the gauges are very close to your face, they should actually look quite sharp, because they are taking up a relatively sizable chunk of your field of view and therefore are being rendered with many more pixels than if the gauges were further away from you.
As far as things that could affect the visuals in your HMD, I can think of a few very important ones:
(1) I don't know how it works with the Odyssey, but on the Rift and Vive there is an adjustable spacing between the lenses, called IPD adjustment (that stands for inter-pupillary distance). This is an adjustment that matches the horizontal distance between the lenses to match the spacing between your own eyes. If this isn't set correctly, it will not only make things blurrier for you, but also might contribute toward discomfort or headaches when using your HMD.
(2) Lens 'sweet spot.' It sounds like you're already aware of this, but yes, it's real. It's critical that you have the HMD placed at the right height in front of your eyes to get the central field of vision sharp. This is similar to the importance of IPD adjustment, except instead of adjusting the lenses sideways for sharpness, this is a matter of moving the lenses up and down relative to your eyes until you find the range of peak sharpness.
Again, I'm not sure about the Odyssey, but since it's higher resolution than my Rift, I'd expect it to look better than the Rift. If (1) and (2) are set correctly, then what you see in the center of your field of vision should be 'sharp', but somewhat pixelated. In other words, it won't look crisp due to being able to see individual pixels, BUT those pixels themselves should still look sharp, not blurred.
The last thing that makes a very substantial difference is supersampling. Supersampling is a method of anti-aliasing that can really clean up the visuals in VR but requires a lot of extra processing power to do so. There are two places where this is set--SteamVR has its own settings for this, and within AeroFly they also have a slider for supersampling (it's called 'Render Scale Factor' in the Aerofly menus). If your graphics card can handle it (and a 1080ti should definitely be able to), setting in-game supersampling to something between 1.5 and 2 should give you a clearer and crisper view of gauges and smaller text. Ideally you should only have this set either from SteamVR or within Aerofly, not both places.
If everything is working correctly and the above items are setup correctly (and assuming your own vision is good too), the gauges in all the planes should be readable from normal distances (though probably not as clearly as you'd like), and easily readable if you move your head a little bit closer to them. From your posts, I can't really tell if your problems are just due to your expectations being too high for current-gen VR systems, or if there is legitimately something wrong with your setup.
TL;DR Gauges in VR will definitely not look as good as even a 1080p desktop monitor--you will see some visible pixellation. However they should still be readable and if you move your head closer to them they should be *easily* readable.