"Here it is said well, how the cover works.
My opinion is that the hives has too much ventilation. a mesh floor and a huge upper hole in summer.
In winter Run Apiaries use 2 inch insulation board."
You are right that the hive could have "too much ventilation". That all depends where you live on the planet. If you live in a mild climate then I don't think it is a concern.
First of all my (SBB) screened bottom board has a tray that slides underneath to control the air flow. I usually keep it on through most of the winter.
During the summer months here in New England the ventilated inner cover that I have works great, I think. If there is bad weather (rain/cold) you could still insulate the VIC with foam. During the winter you could also insulate the VIC with foam. I wrap my hives with 1-3/8" (corrected 1/12/10) foam laminated with aluminum paper. If you look at the picture on page two you can see that the foam is taped over my hives. Inside the VIC you can cut this same foam and place it around the walls of the VIC, similar to what the Honey-Run-Apiaries design has. The aluminum wrapped foam does not get destroyed by the bees because it is protected by aluminum. You can also fill the inside of the VIC with absorbing material as many people do. With my new design, which has the upper vent hole above and within the VIC, you now have an air flow through the VIC which allows the absorbing material to absorb the moisture. This is what I am doing with my second VIC I just built.
This new design also includes a rabbet on top so that I can hang frames for the summer. If I want to hang frames during the winter I can place the frames in the center where I would usually have the honey bottle but I would not use it during the winter for frame feeding because I don't think the bees would come up during cold weather. In a milder area they might. I have the honey bottle right now in the center hole and insulation material around without sealing the front vent hole.
Like I mentioned earlier, if you don't like the amount of airflow through the side screened vents you can make "flaps" or covers so that you can regulate the amount of air flow through the VIC sides. During the winter you can keep the solid laminated foam insulation.