Thank you, Dave.  And thank you, Mike.   This is helpful,and quite educational, especially the lengthy background explanations.

I have now pruned all but the main unnumbered .exe and two of the more recent .exe app revisions, for all seven DXLab apps.  I'm stuck on one remaining question before I do anything further :  

The main unnumbered SpotCollector.exe and two of the more recent SC .exe revisions, are not in the SC Folder where they should be found, rather, they are in the main C:\DXLab  folder.  Searching further, I found inside the regular SC Folder two very old SpotCollector .exe updates, dated from years 2006 and 2010.  So, before I go ahead and delete the old 2006 / 2010 updates, and then move the other three .exe from C:\DXLab to C:\DXLab\SpotCollector, thought it a good idea to check with the experts.  Thanks.