on the contrary, perforated panels are very good in filtering dust, just get the filter to cover the holes in the panels to prevent dust from getting it.
Positive air pressure by blowing the air into the case can also minimize dust but you have to clean the dust filters regularly. It is impossible to cover the gaps between the drives, usb ports etc, in fact not necessary. When there is positive pressure, the air will move out of the case by the small opening, so no dust can ever get in.
I only clean my dust filters once a month and the interior of the case is almost dustless, maybe clean it once a year.