Mike -- Thank you very much for your timely and informative reply. I had put that FocusLock button in there as a placeholder, with the intention of doing what was needed. It appears that it truly operates independently and automatically, which is wonderful. There is one little bit in your report that concerns me though, and which may lead to additional logic after all:

It [FocusLock] doesn’t do anything until guiding has started. I had been “prefocusing” manually with FocusMax but just stopped doing that.
How might this be incorporated, then, for long runs of unguided images? A typical photometric time series might be hundreds of short/unguided images over several hours. It would be OK if FocusLock were simply not an appropriate technology for such activities. Or perhaps I would need to try to start the guider and let it run during the entire time series, which would be OK. By default, ACP will currently add up the total exposure duration (images times duration) for a target and start guiding if the total exceeds the maximum unguided exposure interval. Assuming there is a guide/focus star available in the ONAG + guide camera's field, that would make FocusLock work in that scenario.

Let's have a phone chat after you get a few more weeks experience and see if you have further thoughts. Thanks very much for all of this and or deciding to become a customer!!