Window division of 2/3 fixed glazing and 1/3 openable

Since I would like to have the frame offset to the sash surface so that the window division is narrower

I don't understand a word of that – mind you, with industry background.

Is my estimated ratio correct?

The so-called "golden ratio" is timelessly popular and is about 61.8 : 38.2 % division.

I think it depends on the usage. For example, we have in the utility room, where we also hang laundry, the small part fixed and the large one as a casement. This way the humid air can escape much faster and even when tilted the volume for dehumidifying is larger.

In case it is not too late, we also have such windows in the kitchen and bathroom. Because we found it visually nicer that way and the dimensions fit better. However, it also has a mullion, meaning there is no frame left in the middle and you can open it completely. I have also attached a picture.

I also attached a picture once.

What is that slat above the lift-and-slide door? And under the gable a lamp outlet (?)

To be honest, I don't know what the beam is supposed to do there, maybe as support? A camera is supposed to be installed directly under the roof, lamp outlets are on the right and left.

What do you want to do with the camera? For people or face recognition, way too high. Just to have an overview of the garden, okay.