Commission a reinforced concrete structure design - adaptation of a traditional design, single-family house

I will commission the preparation of the adaptation of a building project - currently in traditional construction (hollow block + columns) to reinforced concrete construction (reinforced concrete).

I am looking for someone with experience in designing prefabricated walls - I would like it to be reinforced concrete, well counted, not oversized, rather than a reinforced concrete bunker.... Precast concrete wall companies use very little reinforcement even for multi-family buildings.

I have a couple of projects to redo, we are starting with a single-family, 2 unit building with a total area of about 200 m2, 2 stories and an attic/loft.