When I'm developing PCB, I decided to split the PCB into 4 main zones, absolutely symmetrical from both sides:

It was a little bit challenging to provide proper grounding w/o undesirable current paths. I did some minor mistakes with the grounding in  REV 1.0 but I think I fixed it all in REV 1.1. 

Also, the additional spacing between unisolated GND and isolated GND was added. 

I used 0603 parts (minimum size) for hand mount ability.  Unmounted parts -  temperature sensor(U9).