Teams Only cutover

Hi Joe McGowan,

When you enable "Notify the Skype for Business user" it can take a few hours to propagate the setting.

As you have mention, the best practice is to activate this for example in a Friday night, few weeks before change to Teams Only and to inform also the users about the change.

Is advised that you create a Change Management Program with champions within the size of the organization and prepare all before all dates.

Here you have more information:

Plan for your Skype for Business to Microsoft Teams upgrade - Microsoft Teams | Microsoft Docs

Teams upgrade planning workshops - Microsoft Teams | Microsoft Docs 

Also is advised to contract a company with experience with this kind of project that also has other practices and will help you better on this Journey.

Best Regards,
Nuno Árias Silva
MVP Office Apps and Services
https://www.nuno-silva.net