Thanks for answering.
I did create a custom package but did not find a guide as detailed as yours so I ended up making one without any customization. Just to make it able to go /silent. (Can't believe Graphisoft is not supplying an MSI for installation)
I ended up copying the entire "%appdata%\Graphisoft\ArchiCAD-64 18.0.0 SWE R1" -folder from a preconfigured profile and deploy that folder along side with installing my custom package.
Probably not the right way to go, but it works