in this case,
custome have uneven window frame， so there is no room to install inside the mount and no space to let the louvre moving,
so we decided to install face fited on the window frame.
we used 42mm*42mm wood to put on the window frame,then hinged the shutter panels on top.
Picture 1: how it looks after install.
Picture 2: the pictures shows the 42mm×42mm wood put outside mount，then hinged panel，
Picture 3&4: shows on the side view when shutter closed.
Picture 5 : for this type of installation. we can see there is no gap on side/top, we do the panel bigger than the stand way.