This timer could be good. But better have it on the Source DockWe use OBS Studio at my church with a multi-camera setup. With the idea that changing camera views enhances visual interest and it breaks up the monotony of a single head-shot during long segments, it is nice to rotate through the different cameras. The problem with changing cameras manually is that you need to keep track on how long the current camera has been displayed.
I wrote a Lua script to do this, but it requires a manual installation and the installation of your source dock plugin. If you added a count up timer that starts automatically when the scene becomes active I could close my project, because your plugin would do everything mine does, but better.
See Scene count up timer for more information.