We have a change management process in our company as well and when I implement change with our logon scripts. I have three implementation phases before any actual deployment to a wide audience.

1) Proof of concept. Test script written and tested by me and various test accounts on different platforms.

2) Beta. Script deployed to various users in the enterprise, typically within the IT dept.

3) Pilot. Basically a wider beta rollout that includes a sampling of users from across the enterprise.

This shows the higher-ups that due diligence was done during testing and that you've made every attempt to discover the "intangibles."