For more information about how to distribute a program through group-policies, go to Microsoft Support Site:
https://docs.microsoft.com/en-us/troubleshoot/windows-server/group-policy/use-group-policy-to-install-software
The installation package supports the following gears for Windows Installer:
-q, -quiet, -s, -silent = silent install
-passive = progress bar only install
-norestart = suppress any restarts
-forcerestart = restart no matter what
-promptrestart = prompt if a restart is required (default)
-layout = create a local image of the bootstrapper (i.e. download files so they can be burned to DVD)
-l, -log = log to a specific file (default is controlled by bundle developer)
-uninstall = uninstall
-repair = repair (or install if not installed)
-package,-update = install (default if no -uninstall or -repair)
It is not possible to change the unit letter through GPO.
Installation links (Download the first MSI-file and complete with one of the 32/64-bit versions):
https://secure1.storegate.com/public/storegatecloudfolder/windows/StoregateCloudFolderInstaller.msi