And some additional comments on the evolution of wireless networks in my talk from Battlemesh last year: https://www.youtube.com/watch?list=PL3bvPCw5QCLJ-VJPamVeQx-U...
One part that made the problem more tractable was that we both ran the network and made the devices. This almost never happens. It means we could optimize the devices for quality and supportability instead of making the usual consumer device tradeoffs (is it pretty enough? cheap enough? glitzy enough?).
So the argument to over-estimate or sand bag, and fold in better solutions with the boy scout principle seems to me the best way to make a brown field site green again.
I’ve had one experience of this which totally worked. Time to implement features went from weeks to hours. I’m currently trying to apply the same method again with mixed results
During the conversion phase from relative sizes to absolute sizes (which should be based on historical measurements, not aspirations), you can choose to add a bit of extra time so that people can work carefully and fix things rather than feel rushed. That's often a very good idea.