Workflow for experimental changes to configuration

Two types of workflow change the configuration, back-end and front-end. I got attracted to Fvwm seeing the endless possibilities to change the front-end. “Getting Things Done”-oriented FVWM config was one of the first topics that I read. What’s the best way to maintain control of our tasks and manage the windows? The Fvwm KISe ready-made small configs focus on that. I am interested in how nested X server and other back-end configs do it.