what is the optimal oversampling setting number should I use in the SteamVR video settings? I read the OP mentioned 400% (4.0 setting in SteamVR I assume), but elsewhere people seemed to recommend 140% to 250% (1.4 to 2.5 in SteamVR video settings), so I am a bit confused here.
I'm glad you are enjoying the VR. The experience is totally different than flat screen, and in my opinion, far superior.
About your question, it depends on the power of your PC and the graphics card you have. You have to apply the maximum supersampling that your PC allows, in some cases it will be 150%, in others up to 500%, depending on your PC. Try it little by little until the video starts to be jerky, then lower it a little.
Instead of touching the general Steam VR setting, it is better to leave this general setting at 100%. Then go to the Steam VR Video menu, and there you will see an option to adjust the definition in each app or game. There you choose the video player you are using, and try it at 150, 200, 300%, and so on.
This is because each app or game consumes different resources, and one will run at 200%, another at 300%, others only at 100% or less, etc.
Depending on the player you use, look for a Sharpening option, which increases the video detail. I recommend Deo VR, or even better Virtual Home Theater or HereSphere, these two are the ones that give the best graphic quality, but they are a little difficult to use.
I was still able to enjoy one porn session, and even from 4K to 6K, you can see a difference, the grid effect is far less visible. Melody Marks looks stunning and you can even see details on her skin (more details than with the Oculus Go). You can also see that some studios do a poor job and even their remasters are crap (Naughty America for example) where the actress looks like a giant.
Like I did with the Go, I use SkyboxVR to play the files. I had to buy it for the Quest 2 as I didn't find a working apk for the headset.
I'm glad you made the jump to Quest 2. The higher screen resolution is noticeable. I recommend you try some videos at 8K from SLR or CZechVR, you'll notice the difference.
Yes, the Naught America remasters are really bad, they look terrible. The girls as giants thing happens also in many titles at 8K, many studios are using a Canon camera that makes everything look giant. This is solved by reducing the image diameter or zooming in the player. Instead of Skybox I recommend you Deo VR or HereSphere for Quest 2, the movies have more definition and especially the last one, it has many options to reduce the size of the giant girls.
Now that you both have VR glasses, I hope you can recommend us titles you like. I recommend quite a few but my tastes are pretty simple and standard...