Just found out about the GBC and was wondering if it can be used with the Mac versions of the games and if so how would I set it up ?

I haven't used the Gold Box Companion yet, and I don't have a Mac, but I took a look at the instructions of GBC. It uses it's own setup program, and that only comes in Windows executables, so there is now easy way to run it on the Mac versions. And some of it features sound like they also use a program to hook into the game, so that would also be plattform specific. Maybe it could work with some kind of Windows emulation, but I don't know what's available on Mac for that.

Maybe you could ask the creators of GBC about the possibility of Mac binaries/compatibility?

As I thought, but thank you.

I'm not sure if this helps, but...

Here's some discussion on how GBC can be used in Linux with Wine (it's in german, the second link is Google translated)
https://forum.ubuntuusers.de/topic/goldbox-rpgs-gold-box-companion/
https://translate.google.com/translate?hl=en&sl=de&tl=en&u=https%3A%2F%2Fforum.ubuntuusers.de%2Ftopic%2Fgoldbox-rpgs-gold-box-companion%2F&sandbox=1

Wine is available to Mac as well? It also has frontends like WineSkin and WineBottler.
http://wineskin.urgesoftware.com/tiki-index.php
https://winebottler.kronenberg.org

One possibility is to use use a virtual machine and install Windows XP on it.

Thanks for the information.