Panoramic 360 texture file correct size, weight and extension

Hi,
I’m doing a virtual tour in Unreal Engine by putting 360 panorama images as a texture in a big sphere.
Does anybody know what should be the resolution, size, weight and extension of these texture file?
I had heard that the .tga extension and 4096x2048px was good, but I’m not sure…
Thank you in advance for your help!

I’ll leave this here:
https://docs.unrealengine.com/en-US/…rop/index.html

As for file type, .HDR and .EXR are 32-bit and stores IBL info properly. I don’t recall if UE4 can work with 32-bits. I want to say that 16-bit is the highest without diving into cpp.