When I was first installing my system I had similar questions trying to figure out orientations that would work with various sensors on my windows and doors. I started a thread here: Door/window sensor orientations - Support - Surety Support Forum (suretyhome.com)
What I learned is that the magnet (smaller piece) has to align with a spot on the sensor (larger piece). It just has to align such that when the window/door is closed, the magnet is pulling the switch in the sensor, and when the window/door opens, it releases it. You can actually hear this action in the sensor if you are in a quiet room and hold it up to your ear. So you can test different orientations by lining them up the way you want when it is closed, and then simulate the motion that will occur when it opens. Then simulate the motion back to closed again. If working properly, you will hear the faint “click” of the switch as you simulate each motion. As long as you get that click on open and close, it should be OK.
I also found that the IQ DW Micro-S is quite a bit smaller than other door/window sensors and might work better for you with windows in that picture.
Also, since I too have black windows and doors, I painted my sensors so they blend in and you don’t notice them. This likely voids the warranty on the sensor, but it was worth it to me and they still work fine. I just used a light coat of satin black spray paint. You can be pretty careless when painting the magnet since there are no electronics in there. The sensor you need to take care not to get paint inside. You can also purchase a small roll of 3M black double-sided foam tape to use instead of the white tape that comes with them.