I used 0.2 / layer with MG PLA
I used 5 top, 5 bottom, and 5 outside layers. As the walls are only 1mm thick that will just about fill the bill.
This was a quick and dirty design job
If I had taken the time to do an angled roof section rather than a 90 degree roof next to the fan I think this object would have printed with no supports. That would have saved a lot of time spent on the post print removal of the interior supports. If I ever need another one I will do it.
So, remove the supports, pop off the two knobs, angle the device into the enclosure, and pop the knobs back on. I did not do anything to tie this thing into the box as its a close fit. I did add a small piece of double-sided mastic (foam tape) under the device's USB tang to hold the bottom onto that area.
If you want to tweak, have fun...