Apognophos, thanks for making me think!
My understanding of the physics of the water canopy is as follows: Material can either orbit the earth or bear directly on it (I'm unaware of a third option). Therefore, water can either orbit the earth (something like the ice rings of Saturn) or ‘float’ in the atmosphere (something like clouds and vapour), which in turn bears directly on Earth’s surface. If the water canopy existed toward the outer reaches of our atmosphere (not actually very high up at all), it would indeed turn to ice fall straight down.
As for the effect on carbon dating - I’m going to have to re-think that… my head hurts.
Also, you have made me seriously doubt the 7000 year thing. Maybe they do intend to allow for millions of years. It’s just that, a simple reading of their literature gives such a different impression...