My son gave me a Presidential Roller Ball kit. It is a Woodcraft model #124767. The kit is missing the tubes. I found the instruction sheet online. The instructions sheet lists a part number for the tubes but Woodcraft no longer carries them. They are 10 mm tubes which I can buy at PSI. However, the Technical Support at Woodcraft does not have the length for the tubes. Does anyone know where I can find the length of the tubes?