First time logging onto the revised site. Good thing I had twenty stabs at logging on, sheesh.
Anyway, wanted to contribute to discussion by sharing a DIY sliding sternum strap idea that uses zippers: http://matthewkirk.blogspot.com/2016/01/the-not-so-fastpack.html
Description of system starts on 4th paragraph. Pictures included in link. Sorry, too lazy to try posting pics here. Was a workout enough to log in. Happy New Year!