it is not what dev would recommand but usually when I do an update i simply expand the correct templates and restart the afflicted services.
You must also pay attention if there is not migrating informations that should be executed before that in /etc/e-smith/db subfolders
Then you can update the config db to remove the anoying server-manager message.
If you have no modifications like compiled module, kmod etc, you can also try the update at night for the reboot, and cross your finger everything will reboot fine, as you will have to wake up early to check what goes wrong otherwise.
I usually reboot when a new kernel is available or a lot of services have been updated at once.
Remember rebbot will stay the safer way.
Reboot after update is a current problem for admin, it has been a choice done by the dev team as a lack of ressources to handle all the cases to avoid this. The dev team is still missing ressources to work on this, so if you have spare time or money
Update are not necessary that often, so a policy with warning 1 day prior to the update should ba also a good idea.