I used the corsair hydro x ecosystem for this build though i ended up switching out the cpu block for the mono block by EK. I used Y fittings to create a duel loop by splitting the flow from the pump out port to the gpu block and the cpu block and then I used another Y adapter so that each radiator converges at the reservoir like a serial style loop. It is all hard tubes with thermaltake fittings.
Where do you even sell a system like that? When i upgraded the last time i tried to sell my previous rig and nobody seemed to want custom wc in a complete rig...