> Monitoring first: we have a strong desire to increase this but we're a bit at a loss as to what a good light-weight solution is here

Prometheus is designed with this in mind. Instrumentation is easy to add and takes care of things like concurrency and state maintenance for you, so you can sprinkle it anywhere safely. http://www.slideshare.net/brianbrazil/python-ireland-monitor... goes into this a bit more.