I have a Scene Capture Component 2D, a Render Target, blueprint nodes setting the spectator screen mode and texture, the whole shebang. Despite all this, I can tell the spectator screen that pops up is “zoomed in” or cropping most of the image off my screen so I can only see the center of what’s in view. I remember this working a lot better in previous versions of the engine on other projects so this behavior is new to me.
I just noticed this “zoom in” seems to happen no matter what the spectator screen mode is. When I set it to show what the HMD is seeing, it’s way more zoomed in/cropped than what the headset is seeing, no matter what setting I set it to.
I just did something similar and was about to post the answer here :). I set the resulution to 50 percent inside SteamVR settings and that worked too. But with mine the viewport has to be launched in windowed mode and manually clicked to full screen icon.