Thanks for looking at this Mathias.  
I had looked at the docs then at Jungles script (Name as Folder)
    $file = $arr[$i];
    $s = PathGetFileExtPart( $file );
    $name = $prefix + "*" + $s;
    $files = FindFiles( $src_path + $name );
    $n = arrayCount( $files ); & thought that I could also give a string variable.  I looked at my code today & realized I'd omitted that bit!  (& probably other things...)
I think you're right about the UI.  
My idea will be best handled by MCs own tools, so I will need to study the MC.<command> features more closely.  That could give me some great automation.
e.g. I like the ability to load the explorer panel filter via a button - "
MC.Explorer.SetViewFilter" - is very useful.  
So I need to play with the other commands.
I think that the ideas I had clash between using MC script & taking over parts of the MC UI environment.
I am not 100% sure of boundaries yet.  
I can see DOS .bat type script is cumbersome/weak compared to the MC script, & that the script is out classed by C++ MFC.  
Now I'm learning more about using the right tool for my job.
I think a button script calling MC commands could allow me to -
activate in-line edit 
paste in clipboard contents
copy/move
Which might make a useful button.  
Using my new MCscript based buttons has improved my work environment a great deal.
I noticed on the 1481 update today that array processing by functions has changed.  If I understand this correctly it looks like scripting will be quicker & easier.  This will help me move forward in my experiments.
OT - I found a handy free 
regex tester that anyone wanting to use the MCS regex functions might find useful - 
http://antix.co.uk/Projects/Regex-Tester  The variables it shows seem fully compatible but I haven't tried them all yet!