GoForSmoke:
You still need to figure out how to code so that not a single cpu cycle is missed in the timing code. Gooooood luck!
I already have that figured out. I just purchased a GPS shield, a programmer, a couple crystals, and a data storage shield. The next step is to shift to using a crystal as the clock and collect data to characterize the crystal. I figure once I am setup that it will take weeks to measure each crystal. I will post data when ready.