Hi Robert,
I understand your question but I do not see your problem.
You asked
"How does one classify a Scott# 727 from a Scott# 727a/vi or 727b..??".
A Scott 727 is a normal printed stamp (like the ones you have shown), while a Scott 727a/vi has the silver inscriptions omitted and Scott 727b has the silver inscriptions double printed.
Here is a Scott 727a:

For Scott 727a or 727vi, I would recommend that a VGG certificate is obtained as these can be 'created' by removing the silver print.
I do not have a Scott 727b with the inscriptions double printed, but this is a Scott 726ii which is doubled , kiss print.

- stamporator -