@nielash thank you for your thoughtful writeup.
Unfortunately we've lost our bisync maintainer so this code is effectively unmaintained at the moment.
Would you like to contribute to the maintenance of it? You appear to have a grip on the source which is great.
Perhaps @jwink3101 you'd like to help too - perhaps we should be heading towards the syncrclone way of doing things?
EIther way, I don't really have time to get to grips with the bisync source myself so I'm looking for help.