Running Windows Update on a Primary Domain Controller

I’m trying to find if there is a “best practice” for running windows update on our Primary Domain Controller. Our network runs with one primary and two other Domain Controllers. We’ve been updating the PDC by autodownloading the updates then picking the time to install (which usually requires restart and therein lies the rub). There seems to never be a good time to restart. I’d be interested in thoughts on how best to do this.