1. Unfortunately, I did not understand this question.
Please explain in more detail - when and for what do you want to use tiles with different resolutions?

2. There may be three reasons (in Texture Importer):
a. Wrong size of texture.
b. Compression. Try to set None.
c. Mipmap. Try disable it.

3. Texture Importer / Wrap Mode - Clamp.

I just bought your Upano Asset which seems very interesting !

I am working with hires 360 images (27000x13500 pixels = about 360MPixels.
I am trying to get the best resolution with UPano, so I converted the 27000x13500 equirectangular panorama to 6 cube sides 8192x8192 (the maximum resolution of a texture in Unity) to get a 6x8192x8192 = 400Mpixels.

I have 3 questions for the moment :

1. Would it be possible to manage tiles with different resolution, as virtual tours usually do ?

2. If I compare the result in Unity with what I get in Panotour (the software I use to make VTours) the resolution is very low in Unity altough the number of pixels is about the same.

3. I have lines around the cubefaces edges, any idea why ?

Best regards !

Philippe