Hi,
Intresting video. He has some nice ideas like the perspex inner lid.
His idea is actually similar to my cheap and nasty incubator but I think you're right to avoid open water and electrics whenever possible.
If you use substrateless incubation in the egg boxes I think you will have zero problems just using waterbottles as a heat buffer.
From his comments I'd say BP eggs are a little hardier than the tree pythons.
They won't need that amount of fresh air pumped in at least - just opening the boxes to check on the eggs will be enough if you are as impatient as I am.
dr del