From @risa2000 grid test image modified slightly
I have set the Camera at a distance of 0.5m from plane. It may be slightly big but will hopefully be of use. I can reduce the grid size if requested. Is quite hard to get it perfect.
When you just replace the Pimax:default.JPG and just use the Pitool with nothing on it seems to be rendering to infinity and it does not look right. Im a bit unsure how it is here so ill leave it to the smart guys but it does feel better. That could be due to the fact that the sizing may be slightly off.
Hopefully you can find this useful