B looks like it would get rained on. I assume Madrid does get some rain, at some point in the year..
Yeah, right, and this year more often than any other year.
Covered area with roof (area A) its the chosen one i think
I will just have to buy something to protect shelf from sun the few hours that sun hits that area 
At the very least I would keep some kind of very sheer material covering the miners, like maybe the mesh used in a window screen. This would deflect most water droplets wherever they may come from. Hot miners won't condense water but the roof will and a few drops falling down and poof.