At the moment I do not want to recommend any of the hives I have built for reproduction. They are constructions with which I try to reproduce natural conditions or to specifically support the symbiosis of bees and book scorpions. These constructions are not yet mature, maybe I will discard them again and break new ground.
When building my hives, I more and more follow the characteristics of natural tree caves. 45 million years of evolution of the state-forming honeybee have perfected the life of the bee in the tree cave. I think it makes a lot of sense to orientate oneself to it and reproduce as many characteristics as possible.
We already know some characteristics of the tree caves. Above all, they have excellent thermal insulation and their geometry is slim and high. There is no significant natural ventilation and water vapor diffusion plays no role due to the large wall thicknesses.
The problem of excessive humidity in modern hive systems is, in my opinion, a problem of inadequate thermal insulation. Moisture itself is not the problem in the hives. Also in tree caves and hives inhabited by bees, very high humidity and condensation occur at the edge of the cave. With a low level of external insulation, however, condensation already occurs during honeycomb construction. And that should be fatal for the bees.
The D-lid is only a temporary construction to reduce the high humidity in modern hive systems. More sensible, but also more complex, would be the installation of a reasonable external insulation on the sides and on the cover. With this kind of insulation, the floor could also be closed. This construction would be much closer to the characteristics of a tree cave. It may well be that condensation is desirable in certain areas of the hives.
The Diffusion-lid is only a substitute construction to cushion the negative consequences of the low thermal insulation in bee hives. More sensible, but also more complex, is the installation of a reasonable external insulation on the sides and on the top. With this kind of insulation, the bottom could also be closed. This construction would be much closer to the characteristics of a tree cave. It may well be that condensation is desirable in certain areas of the hives!