I only use one machine, but can merge seperate renders in the same way as if I had 100 computers.
Maxwell has a great sun positioning system and physical but cloudless sky.
If i’m going to use a photo background for an exterior render, I usually set the sun position and time to match the photo. Using this I can then add the background after rendering, with the correct sun position.
Another way is to use the physical sky & sunlight and use a HDRI image for the background. Is this possible in WinOsi?