Luke, are you sure that you cannot fit a 140mm fan on the back of the case inside? From the pictures it looks like if you mounted the top radiator in a pull config with the fans between the case and the radiator, and used either 45 or 90 degree fittings for the rad, you could keep the tubing out of the way for a fan to sit on the back of the case.
Either that or you could flip the rad around. Any reason you have it the way you do?
I don't know where you see the fans mounted + RAD ,I was thinking about this earlier and will probably give it a shot when mounting the RADs next time ,mounting RAD like NexXxoS that requires 3M screws and about 0.180" to spare inside the RAD (guarding shim stock ) + the fans+robber shims is not easy I have done this in my last build and almost had a fit ...screaming and yelling for few hours
You've inspired me to do a very similar loop for my gpu! For the tubing, where did you buy the rubber tube for bending? Also, what fittings would you recommend or what were the ones you used for your Primochill Rigid Acrylic.