Many thanks to all of you who contributed to answering my question, especially StainlessS. Some of the discussion was out of my league, but I have the plugins and script working and the outcome is exactly what I need.
I luv it when a plan comes together!@#!
While it is now acedemic, raffriff's comment "I for one don't think Avisynth is the right tool.." does beg the question; "What is the right tool?
Again, many thanks.
Boris.