I am working on the base image now. My next step is to run sysprep. I am wondering why the instructions don’t mention anything about shrinking or compacting the VHDX file so it takes less space. Isn’t that a common practice when creating base images?
To be honest I don’t think you would bother since VHDX are dynamic so use the space as required up to the max allocation. If you are concerned about space you could look at setting up a diff disks that extend a master disk . Your master disk has your O/S , service packs and some common utilities. The diff disks simply reference this without duplicating the space taken up by the master disk. You can even do the creation with PowerShell commands.