Sounds good to me. Just looked at your Sump Pi backup logic again and I think it is pretty much filling up the wendy butts as fast as it can do safely anyway. If it takes a while to pump all the water upstream (which it will by the looks of it), that's okay anyway. I think the stat we're looking at of roughly maybe 1 hour to fill all the upstream water butts is pretty impressive.
EDIT: If you want to make changes, I'm happy to delay testing it until next week anyway. I'll be setting up the new Pi VMs this afternoon.
Water Backup System - Overall Design Strategy
Re: Water Backup System - Overall Design Strategy
There were a lot of assumptions in my calculations, so it may take a lot longer if there are too many bends in the pipework. I doubt that we would struggle to fill all the upstream water butts in a single night though.
Terry