Designing for Large Scale (Graphic Design Question)

Hi there,

I am designing a concept for a small hut which would have 2 sides and a front. I wondered what the procedure for adding a bleed would be for such a large scale design? Should I add something like 5cm? Or more/less?

Also, what software would be best to design this in? I was thinking of Indesign or Illustrator.

As the front would be around 7.5m x 2.5m and the sides would be 3m x 2.5m, should I design them scaled down? Also, should I design them as 3 separate artboards so they flow into each other?

Any suggestions would be great!