There is a file where those configs are stored: ../config/pushPullSetup.xml, or if using the linux installer: /var/evostreamms/xml/pushPullSetup.xml
You will not want to trigger a pull event off of the codecs updated message. That can happen multiple times for a given stream. It all depends on whether a stream has varying information (GOP size, resolution, etc can all change dynamically). Stick instead to "InStreamCreated".