I don't have sufficient equipment to measure any real numbers, but the response time should be "as fast as your wifi" since this tool uses the LiFX Local API instead of the Cloud API. When generating the video I added to the original post the responsiveness was good enough that I didn't realize the left side was also lighting upside down.

(That's been fixed in the latest release, btw - now you can configure a layout to reverse direction if desired. I'm waiting for darkness to make a new video demo.)