The Modder's Documentation has a link to how to add a BUG option, but iirc that was an unsynced UI one.I was going to ask you about that... after fully researching the HOW on Bug Options.
I'd rather add autosyncing to BUG options at some time but until then you could check how Afforess did it in Assets/Python/Afforess/ANewDawnSettings.py. At least you can see from that how to use the Python ModNetMessage.
Mind that Afforess's solution is not completely MP safe as there is a time between the local change of the BUG option and the ModNetMessage arrival when the options are async and when anything happens in that time that is influenced by the option you have an OoS (short though it may be so it will be very rare).
That is why I'd rather put the syncing deeper into BUG.