ᐅ Building a two-story house

Hello everyone.
We are considering building a two-story house. Currently, we have planned a knee wall of 2.20 meters (7 feet 3 inches). However, we were told that with this knee wall height on the eaves side, it is not possible to install a large window including a roller shutter. At the same time, there is another thread where also a 2.20 meter (7 feet 3 inches) knee wall is planned, but according to the original poster, standard windows including roller shutters are installed there. That surprised me a bit.
In my opinion, only a window up to 1.60 meters (5 feet 3 inches) can be installed without a roller shutter, since the box for the shutter of about 30 centimeters (12 inches) plus insulation and the finished floor still have to be deducted.

Can someone tell me what the minimum knee wall height must be to install a large window including a roller shutter? Has anyone built like this before?

Thank you very much in advance for your help.