You could make a temporary SCOM group with all the objects you wish to place into maintenance mode. Then you can place all your objects into maintenance at once using the group drill down in Squared Up, I find that SCOM seems to recover quite quickly after doing this.
And edit the variables as per the article to specify the group name and the number of minutes that you wish the group to be put into maintenance mode.
As you can see from the screenshot above, I have a lot of maintenance mode tasks that are run on a daily basis. Also I have five groups that can be used adhoc to schedule maintenance mode on systems/servers that arise out of our CAB meetings. So far this has worked flawlessly.
It also has the advantage that any issues with the servers during the outage window all alert at the same time, i.e. when the window ends.
Personally I did a Orchestrator Runbook that looks at my collection for my maintenance windows and places them into maintenance window on a schedule. It was pretty simple runbook to write and it made it so that as a machine gets added to a maintenance window it automatically gets added to my runbook.
We also use Orchestrator, but slightly differently. This specific customer uses scripts patch systems, and before they patch, they place a file with the servername in a specific folder. Orchestrator checks the files in this folder every 30 seconds, picks up the name and puts the specifc server in maintenance mode. If the server is already in maintenance mode, we add 4 hours to that specific maintenance window.
If the server belongs to a cluster, the cluster will be put in maintenance mode as well.
Slight change that you may be interested in…we use a SCOM Monitor to pick up when the WindowsUpdateClient puts EventID 22 in the event log. This gives the User/OS around 15 minutes for a reboot to occur if your updates are automated.
Then use a Command Channel to run a powershell script on the management server to put the device that generated the alert into Maintenance mode for around 30 minutes.
If you have a set time window, you can obviously modify this to suit your environment. I believe Tao Yang had a guide to this for an older version of SCOM.