Attic wall height

Hello everybody,

Please let me post in English since i don't have command of German. However, responses in German are welcomed.
We are designing some row houses with terrace roof, intending to place solar panels on the roof. Nevertheless, i would go for an attic height of 900 mm, due to safety (falling) reasons.
I am afraid a taller attic will mask the EV panels. Should i limit the attic height?

Thanks, Dan