Basically you create two groups in WMS and first move all clients to the first group to make the upgrade to 9.1.3129. This you do the last thing before you go home for the day (or from home if you are so inclined). The next day you move all the clients to the second group with the upgrade to 9.3.1129 before you go home. This will cause the leaste amount of disruptions. Even if the client promts for a reboot there is the option for the user to postpone this until the next time the client restarts.