Right, I am noticing this too. Pushing hard on the headset or removing the interface altogether does improve both FOV and the size of the sweet spot considerably. Its probably just my face shape. Because of that it's very tempting to pull hard on the straps to push the lenses as close to eyes as possible, but that makes it such that the facial interface exerts strong pressure on the skin. It's ok for an hour, but for long term this pressure is not comfortable.Drop down to around 76% in global steam resolution and tweak further for individual games as required. Note that
running at resolutions lower than 100% will make the sweet spot seem smaller than it actually is as well as reducing clarity at the centre and I have also found the sweet spot to be very dependant on distance from the lenses. Do try pushing the headset hard to your face or removing the facial interface and getting your eyes closer - if you notice a significantly bigger FoV and sweet spot then you are probably suffering from the overly deep facial interface - you may want to keep an eye out for aftermarket shallower ones or indeed try the few mods that are already out there.
So I'll try to mod it with non-permanent and removable mods. First I'll try to make the lenses hover just in front of my eyes as suggested in this video. I have ordered the headband and the weights, we shall see if I this is the solution. To try to solve the light bleed problem which would inevitably occur if the facial interface is removed, I'll try to add an aftermarket facial interface using some velcro tape as suggested in this video. For the interface I have ordered two version of the same thing - slightly thicker one and slightly thinner one. I just hope the HTC Vive has somewhat similar facial interface dimentions/shape. It does not have to be a perfect fit, just good enough to block away most of the light bleed.
Also I have experienced problems with my USB 3.0 ports. I have a Z170 motherboard with Asmedia controller. The headset was not recognised at all, but then I changed the usb controller driver from Asmedia to generic microsoft driver, it worked. Bizarrely, once it stoped to work and reboot solved it. So in case this problem persists, I have ordered a powered USB hub. Its this one, in case anybody is interested. I don't know if it will improve anything but the good thing about it is that it's powered from another usb port, which is nice, coz I am out of plugs by my computer.
Now on to my experience with RX480. Well.. I get like 30-40 fps in steamvr lobby at 50% resolution. Big screen runs at 75-80 fps in 100% resolution and everything looks nice and sharp. Colours pop. Blacks are ok. In the cinema there is some decent contrast between the bright and poppy screen and the darkness of the environment. Sure, it's not OLED blacks, but it's more than serviceable!
I think, The lab game might be playable as well.
But yeah, on to the sides and away from the sweet spot it's a bit blurry and desicively blurry right at the edges of the image. And the resolution of the screen and clarity of the lenses is just enough to read small print on a virtual desktop in the big screen app. What I am trying to say here is that I would not be ok with any downgrade at all. I'd consider the clarity of G2 as the bear minimum. More of the clarity, perhaps with some 150% supersampling (which I could not have tried because RX480), or with reverb G3 is welcome, but anything less than the G2 level, no thanks, not for me please.
I'll report if I have any progress with the mods.