Onikage,
IMHO and FWIW, the OEM gauge is accurate enough to get the job done. I feel that the lack of graduations on the face is the main problem. I am eventually going to use a calibrated vacuum pump and pressure generator to set my gauge to a given pressure range. From there, I will place my own graduation lines on the gauge face. (I don't care for the looks of a pod-mounted monstrosity mounted on my pillar.) I think that this way, I keep a "stock" look and add function to an otherwise useless device. Before I do any of these mods, I need to finish punching out the basics and preventive maintenance.
Prospero