OK, my thoughts when Plex mentioned a VR app were that it would be great to watch in a place where you could relax, but there was no TV, or no TV which easy access to the PMS media. To me this means relaxing on a sofa, bed, lounge, etc. However, as I've noticed on every other VR platform, the silly things assume you're sitting in a hard backed chair at attention and viewing the "screen" with your head perfectly parallel to the floor. Hell, I don't even do that when I'm watching my TV (from my thread worn Lazyboy)! But, I digress ...
Netflix has a feature where you can set the viewing area (movie screen) to remain directly in front of you. When in the Netflix living room, look straight up and you'll see an odd chandelier. Aim the control (I'm using a Google Daydream 2017 set) at this until the center illuminates and click. Look down and click on the steering wheel icon immediate above the viewing screen. The viewing area will center itself in front of you, and move to remain there if you move your head.
Is there a similar feature in the PlexVR app? I can't find anything in the app settings that might do this and haven't found anything in online searches. I can't watch the media comfortably (aka reclining) without forcing my head down so that I'm looking at my feet - definitely not comfortably. I'd think this was a common issue with any 3D media viewing app so it's probably that I'm not using the correct keywords :(
Finally, as a general VR comment when using for 2D viewing, it'd be nice if you could move the screen further away so you didn't have to move your head to see each side of the screen. I noticed Plex will allow you to move the screen closer, but it won't allow you to move it away. I know VR is supposed to be a full environment experience but when using these to watch 2D movies or TV shows, definitely not a 360D media, having to physically move your head to see the entire screen really reduces the "niceness" of the experience (IMO).