I am setting up several iMacs which have different hardware configurations. I would like to temporarily connect the iMacs target drive externally on my main machine and perform the initial install on it. Once the first phase is complete, I would like to install the drive back in the iMac and allow the installer to finish the second phase of the installation (after the first reboot).
I presume the first phase of the installer only copies the installation file, but the second phase performs the actual configuration of the operating system. I fear High Sierra might perform use my main machine's configuration during the first phase of the installation.
In other words, does the Macintosh use the execution environment during the first phase of the installation?