Sizing per person is a fundamental challenge for all VR headsets. As soon as you can wear it the biggest obstacles is making sure that the user experience is comfortable. I think this article sums it up well: (How to Survive a Week of Virtual Reality)
http://www.polygon.com/2015/3/2/8134273/gdc-valve-oculus-razer-vr
Any issue with the fitting, calibration, latency, frame rate, you name it insert issue, will likely increase the possibility of sickness. I find this to be VR's greatest challenge and tackling these problems is much more important that tackling resolution, or graphical fidelity for games for instance. Yes you'll get a small screen door effect with lower resolution, and games won't look as good if you have to detune it for 120fps, but it doesn't matter, VR is a completely different experience and you'll enjoy it differently than you would other games. That being said, removing the screen door would be nice, but I don't need Order1886 level graphics on a VR headset to enjoy the game.
On that note: I'm not sure if i want to play a P.T. VR game if it looks as good as the PS4 version. That's just a form of mental torture I'm unsure I need to subject myself to.