Maybe other users find this information helpful.
I followed the guide step by step. The installation of the USB install disk was successful with Unibeast under macOS Sierra 10.12.0. But after that, the installation of macOS High Sierra will abort immediately with the error code:
macOS could not be installed on your computer.
An error occurred while loading the installer resources.
Quit the installer to restart your computer and try again.
My only option left was to update to Sierra 10.12.6 and download the full copy via App Store.