How can I configure the universal forwarder to collect the hosts system properties?
You should be able to use wmi.conf to query whatever WMI classes you'd like (win32_computersystem, win32_operatingsystem, etc).
If I search the link provided and search for the win32_* items mentioned there is no reference found. Are there example configurations for System Assigned Ram, etc?
if you look in the example conf file at the bottom of that page, specifically at the wql settings, you should see how to query wmi. For example:
[WMI:LocalPhysicalDisk]
interval = 1
wql = select Name, DiskBytesPerSec, PercentDiskReadTime, PercentDiskWriteTime, PercentDiskTime from Win32_PerfFormattedData_PerfDisk_PhysicalDisk
disabled = 0
index = wmi_perfmon
If you need to know where in WMI to find the data you want, that's probably going to be all google. For example, the win32_computersystem class has a field for TotalPhysicalMemory. And the win32_physicalmemory class has a field called capacity.
I guess another option is to see if the add-on for windows would work for you too. Maybe that would be easier?