Just a quick progress update.
The controller firmware is about 90% complete. Still need to implement servo reversing and some additional tidying up. I also wrote a "configuration program" that will allow you to send all the parameters (end points, reverse, channel assignments, etc) to the controller via the dongle. Attached is a screen shot. We were thinking about generating a Vixen sequence to send programming data, but decided it would be simpler to send it directly. Everything is working pretty well, so I think we're pretty much over the hump from a software standpoint. Next up is hardware prototype testing and tweaking.
A little about the configuration program. The end point settings are the DMX dimmer values that you would determine to be your servo travel limits. You'll have to use Vixen or the DMX channel tester to figure out what dimmer values represent the end points (based on the "default" range). When you enter the values in the configuration program screen and send it to the controller, the software will automatically calculate and scale the travel across the entire DMX dimmer value range. So you'll almost always get the full 256 point resolution. Although if you set up a super-short travel range, it may have to give up some of that resolution. 256 positions is pretty fine resolution for animated decorations.

"Load Configuration..." and "Save Configuration..." allows you to save and recall settings as a file on your PC. "Set Defaults..." will reset all values to what you see in the screenshot. "Program Controller..." will send the configuration shown on the screen to the controller. "Settings..." is a means to setup and save the COM port settings for communicating with the dongle. The "Direction" values are "Std" and "Rev". Everything else is self explanatory.
Cheers,
Dave