Online tutorials for gauge creation

Just found this.

The "Gauge Graphics" tutorials, parts 1-3 are very detailed and oriented towards those creating artwork to be used in gauges.

From what I've heard, there is value in the FS9gauges.h file that's part of the Gauge Creation Tutorial, Rev. 17.  And apparently the examples are useful, although I haven't personally looked at them closely enough to see how helpful they are.