Thanks Jon,
While I have a lot of respect for Dakota Digital they are very pricy. Their calibration approach appears to be the buttom/mile approach you mentioned.
I am just trying to make sense of all of the options and pros/cons of each before I head in a direction and start investing in hardware. There are some pretty inexpensive GPS options on E-Bay but it is hard to know if any of them are worth pursuing.
One of the options I saw was purchaing a set of rings that mount into the dash openings that adapt typical 3 3/8" diameter speedometers and 4 standard 2 1/16" diameter gauges. Again subject to the quality of the speedometer and gauges chosen.
