This is a great renovation systems, that requires a more specialized pose than knuckled, but the advantage is a better insulation and a steel radiant slab leading to better thermal performance, but with steel is really much expensive system.
The tube diameter is 16×2 choice PE Xa or PE-RT (both with evoH oxygen barrier).
Distribution you have to choice between simple manifold and group with reduction temperature (fixed point or with external probe control).
Concrete screed at least 45 mm. (above the knuckle of the slab), must be addict with superplasticizer
LA 45