Originally Posted by Brian Carlton

Before you waste a lot of time, can you simply rig a boost gauge and read the boost at a steady state 65 mph (or whatever your typical cruise speed would be)?

Be very careful with your right foot to ensure that you're not accelerating or decelerating slightly, which will have a significant effect on the boost. You're looking for the pedal position that will just barely maintain speed on level ground (also difficult to find). Then, read the boost gauge and report back with result.