If you can specify start_mod as documented at http://yaws.hyber.org/yman.yaws?page=yaws.conf, I think you can reconfigure Yaws after it has started.
Otherwise, I think you can implement lazy reconfiguration at the first HTTP request: in out/1 check if Yaws has not been reconfigured... I think you can remember if Yaws has been reconfigured in #sconf.ets, see http://yaws.hyber.org/embed.yaws.
When the embedded yaws server restarts is there a hook which will notify
My app needs to be notified when the embedded server restarts, so that
I can configure it again!
Any ideas or suggestions?