Coolermeister, would it be possible on the bottom block (in the picture) to use a piece of 5mm acrylic and tap the acrylic and copper. This would give a slightly larger gap between the tail pieces. If not you could you not find some tail pieces (not the DD high flow ones) that could be cut down but still run clamped tubing? Nice project. Cant wait too see it finished PS i really like your idea of mounting the res on the front of your other wave. It was a shame that you could make it water tight.