This should be documented here:
I did the following and it worked for me:
1) First, I copied the client folder to a local folder and generated an ISS file by running: c:\client\cloudinsight8.3_client
2) Next, I ran through the setup and specified where to install the client etc.
3) Then I either uninstalled the client from the control panel so I could test reinstalling it on the same box, OR, copy the client folder with the ISS to another machine where you are going to run the silent install.
4) Then run: c:\client\cloudinsight8.3_client
Note that I had to wait several minutes after this for it to install.
Do not attempt to use the out of box iss file as this will not work in your environment. You must generate your own as documented above