That looks like a nice working setup! Does it bring the temps down a bit when in use?
My g/h is about 18ft x 8ft x 6.5ft ...much like yours or smaller. Did you had a place where you bought your parts for the system? I was initialy thinking to do someting very similar of what you have just not running the tub through the middle but do more like a tour of the g/h ...like a U shape.