For the vent tubing 1 1/4 inch is specified by NHRA for blown alcohol. NHRA also lists some different types of "approved vent tube". The spec tubing is available on line for example at quartermax for $11 -$20/foot. Spent way too much time looking for alternatives as well 1 1/4 is not a popular ID. Good vibrations sells a simple PVC hose however PVC hose does not stand up well to methanol or oil. The line I used is PVC with a urethane coating on the inside it is actually air seeder hose that I had laying around right under my nose the whole time. In theory it should stand up well but we will see. The urethane coating is intended for reduce wear flowing abrasive material in the hose. You can buy it at most farm supply stores. If I recall this came from the John Deere dealership.