Hi,
it’s simple. First, in the resources subfolder, open E_CaptureResolution and add a new row with your custom resolution:
Then, open the 360_Capture_BP Blueprint, and open the GetCaptureResolution and GetPanoMapResoltuon functions:
In both of these functions, specify the horizontal resolution for your new added resolution setting:
The vertical resolution will automatically be derived from horizontal resolution divided by two. Your resolution don’t seem to adhere to 2:1 aspect ratio though. The whole shader which generates these has been written with that in mind, so aspect ration would be much harder to change.
What I’d suggest is to do the following:
- Take your desired vertical resolutions and multiply them by two (2880 and 4320 end up 5760 and 8640)
- Add these two resulting horizontal resolutions as described above (You can name them like 5k+ and 8k+)
- Render at those resolutions. The horizontal size will be a bit bigger than desired
- In some postprocessing package, such as Nuke, or Fusion, or even image editor if it’s just a still frame, resize them horizontally. This should ensure no quality loss as you are downscaling larger image rather than upscaling smaller one.
Just keep in mind that at 8640x5760 resolution, chances of you running out of GPU memory are significant 
I am still a bit confused as to why you’d need non 2:1 equirectangular map, since you’ll just mostly get a distortion that way.