Fourth and finally, explore what filters and scaffolding you can establish to make the experiment a success.
Filters stop, delay, and redirect the invasive push messages that come in through email, text, and productivity tools (Asana, Zoho, Basecamp, Slack, etc.). One simple solution is to establish that everyone will disable push notifications during their time off. Other helpful practices include setting up out-of-office auto-replies and having a co-worker, administrator, or assistant screen your email during time off.
Scaffolding provides systemic structural support that can help change the culture. For instance, you can establish a new CC policy to reduce the email deluge. Define clear standards for when to loop someone in and when to hit Reply All. If your company uses the CC field to keep each other apprized of the latest, perhaps you can replace that practice with regular update meetings.
You can also create even stronger scaffolding by launching client-facing update tools. Imagine if the Amazon staff got an email every time someone wanted to check the status of a package; they would never be able to get anything done. Just as Amazon provides customers with order tracking, you can provide clients with a web-tool that they can log into for updates.
As your ninety-day experiment comes to a close, ask yourself: Has this change helped my company? Has it made my life and the lives of my employees better?