Want to ask the experts.

[Rapture]

I knew that there was a differece between BCI and "true" RTB regarding size. Is there any good way of telling the two appart?

There are many species of Boa Constrictor... go to the site recommended to view and read about each of them. Many have different appearances, top-out lengths, and dispositions.

Just out of curiosity, where are you located?