@Casuir
Thanks, I should read (and remember) what you said before.
This will be my number 1 task for tomorrow, I keep all the header/
footers, change 3 to 0, remove the mystery data including its
4-byte int vertex count, append the footer data without change,
and test in-game.

A btw, I thank you for including me with GrumpyOldMan but
that's giving me way too much credit. I'm just following along, confused
by things like everybody else, (except Grumpy).

A humorous side note: Did you see Alpaca's comment?

I wish I had more time on my hands so I could work a bit on this, too. Anyways, after you cracked this customer, you should also have a look at the settlement packages (it seems there's some cool stuff in there and it's a lot more flexible than RTW)
We should start charging don't you think?