OK, after a week of headscratching and ah-haa! moments… I now know more than I every wanted to know about lua programing… 
It seems that the Midi Machines feature is not well used. I think this feature could be a much more useful if this website could have a page dedicated to allowing users to post their MM programs for others to use/learn from/modify other than those that come with the program (which BTW could be better commented for those of us who are new to this - which is 99.9% of Users!).
For example, I’m working on a midi machine routine right now, and I’m sure it will be useful to others, but firstly I’m not sure that I’m wasting my time because someone else might have already written something identical in function (I wish!) and secondly, when I’ve got it fully debugged, there’s nowhere that I can share it other than buried in this forum. So perhaps a page on the website listing any programs that anyone might want to submit. Obviously, you would take them as you find them, but the Midi Machine function might find more more traction if more examples were made more accessible to newbies.