Jerry.
Thanks so much for going to so much effort here. However, I feel I may have inadvertently led you down the wrong path. Perhaps my OP was incoherent. Certainly it was verbose.
Anyway, my issue is not regarding the connectivity nor the operation of the app (I am all too well versed in its idiosyncrasies), it's solely related to the fact that the app hijacks the camera screen output - not in and of itself the problem but it does exacerbate it. Why?
Here is the issue - monitoring the exposure, not altering it. Once the app hijacks the screen any internal light reading is hidden. How, therefore, can one determine the correct exposure during, say, a timelapse? This renders the latest and previous apps utterly useless (IMHO).
Regardless, you are very kind to go to such trouble for me - appreciated.