Well, I'm not sure, I'm afraid, as I would want to see more of your document, which obviously isn't possible, but yes, this is "dimensioning" them, deciding on their measurements, which basically boils down to designing them (one of my clients likes dimensionamiento to be translated as design).

I understand the patinillos to be the tiny "patios" in a building where all the pipes go and which also let you have some light, i.e. the air shafts or light wells.

HTH