PCM Documentation

Is it possible to obtain information on OEM PCMs so there is a working knowledge of how all of the tables work together instead of having to work through trial and error to figure out how the PCM functions?

yes, but it's a lot of hard work by some really bright people. Here is a fellow on the Miata forums that has disassembled and documented many of the tables and functions in a Mazda NC Miata ECU. If that's what you are tuning, then you will be ahead of most other platforms...

https://forum.miata.net/vb/showthread.php?t=630805

There are books on some of the Ford and GM PCMs supported by HP Tuners. And I think Cobb Tuning has a good knowledge base for many of their supported vehicles.

Hondata has info for the Honda ECUs with their add-in module.