I apologise for the amazing photography skills (lack of).
Hopefully you can see the red lines I've taken so much time to draw in. The hose from the external rad will go in to the cpu block then from the block to the resivour, then the res back in to the pump. Not all fitted up as of yet because I had to order a few more angled fittings etc.
No one seems to have done a 120 rad on the back of a 650d as far as I can tell, probably for a good reason
I think it looks great though.
I would have put my motherboard in before connecting the fans and tubing though.