Not arguing mate an hey I have no actual experience with rain...

Not arguing mate an hey I have no actual experience with rain water tanks.

I have however looked a buy rural properties and done some research into what as required to secure a water supply. A lot of it is simple logic but also need to make it as cost effective and simple.

In a typical suburban house you could use a simple tank under the eves and down pipe as you suggest, but these guys have very large tanks on larger properties so there is a bit more to consider. Yes I would not want pipes 50m long 2m above the ground supported ever 3 meters even if it was a cheap option