I've had the camera out a few nights now for various lengths of time and have made a few more observations about it.  I wanted to post here to give a bit more feedback on the performance of the driver and also to share a picture that I am reasonably proud of (I won't post many more pictures to this thread since that is straying off topic but this one does fit I think).

Overall, the performance of the driver has been excellent.  I have now taken something like 1000 exposures with the driver and the only lockups I have seen were the ones mentioned above where two expose commands were sent before the first was finished.  The other source of lockups is in taking bias frames.  I was trying to do 0.001 to 0.02 second exposures, and both seem to have resulted in lockups.  Further investigation reveals that it is safe and reliable to shoot very short exposures, however they must be commanded one at a time with a manual wait of something like a few seconds between frames.  I can't say for sure whether this is just Ekos trying to shoot a second frame before the first is fully downloaded, or if there is just something in the camera that is still being reset, even though it is technically "done" with the first frame and the driver therefore thinks it is safe to proceed.  Either way, the problem is not a huge deal, once you know how to handle it, but it is a source of potential lockups which require and unplug/replug that would be a pain on a remote telescope.

On a more fun note, here is the stacked image I mentioned which shows the results of the camera.  This was taken last night using an ETX-90 OTA (a little 4 inch scope) on an equatorial mount.  I have no guide camera so I can only take about 10 second exposures and even then I lose about half of them.  I took a total of 640 10 second exposures.  I have processed 300 of them and 127 were good enough to plate solve and didn't have serious star trails (again, no guide camera -- something which I hope to rectify soon).