VR Box and mobile screen size

Hello,

I am trying to build a VR unity application. I will use a VR box and i am kind of in confusion...
1. the latest version of unity has native support for vr but previous versions do need a plugin. should i go for the gvr unity package or any other plugin? like instant vr or similar..?
2. i cannot get a good and focused image on my mobile inside the vr box (i am testing with a 5.5in screen). Are there any specific settings that would resolve this? Is there any way of making an app to work well in many screen sizes?

Thanks in advance

 

1. You don't need to use GoogleVR SDK. You can simply set VR Supported in the build settings and select cardboard as the device. Any mobile VR that is done with the phone, except major platforms like Daydream or GearVR, are all Google Cardboard.

2. Have you downloaded the official Google Cardboard app from Google Play store and scanned the QR code on your headset?

Since VR Box didn't put a QR code on the headset you might need to Google for one:
https://m.imgur.com/r/GoogleCardboard/HzCCw1M