27 Feb 2012: Here are a couple of my 3D rendered images updated somewhat to include what I hope to add in the near future, the inclusion of the Kingspan Varisol tubes. They are done with ArchiCAD.
Logic tells me that if heat rises, then they are better placed vertically, i.e. running UP the slope of the roof not along it. Copper is so conductive that I am probably worrying too much, but I will ask MGR and KSR about this.