me? I vote single loop for simplicity. There are performance gains from individual loops because hotter components won't bleed their excess heat into other components, but if I were you, I would start with simple. 1 loop. only way for you to know, is to try it yourself by isolating components with loops. Maybe after every component, let the runoff go into a radiator.
the full coverage block looks good. They are very easy and 1 shot does it all for all the chipsets.
I havent tried mixing and matching gpu's in Win 7, but I know you cannot do it in Vista