Glad things are going well with your HX.
Be advised - a ScanGauge will not give accurate mpg info on an HX. An MPGuino costs less but can be very accurate. The ScanGauge however will give you lots of useful data such as engine coolant temp, throttle position, system voltage, and more.
The reason the SG won't read out mpg accurately is that it can't measure fuel use. It gets mass air flow sensor data from the computer. Then it assumes standard stoich air:fuel ratio and so derives fuel quantity. It gets distance data from the computer and so has enough data to derive mpg.
However the HX has lean burn (LB). When in lean burn it's not running at stoich, but far leaner. So the SG assumes you're burning much more fuel than you really are. True that there's an adjustment factor you can dial into the SG. However the percentage of time that you're in LB is not consistent. You need something that actually measures fuel usage.
The MPGuino does that. You wire it to a fuel injector and to the VSS. Two other leads go to power and ground sources. Yes, it's a real do-it-yourself job but it can be accurate within 0.1 gallon or less when you fill up. Have a look here:
OpenGauge / MPGuino FE computer - Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com