Hopefully this helps someone else that needs to shorten their torque tube and driveshaft. The following photos explain how to setup for the measurement and where to measure to and from. Important to remember is this measurement will be the desired torque tube length. The difference between this measurement and old torque tube lengths is how much the torque tube and driveshaft will each need to be shortened. There are many methods to perform the actual shortening so I won't get into that here. I will give a shout out to Rusty from Dirtys Speed Shop who taught me how to do this and shortened my torque tube and driveshaft.