I made the mistake of purchasing a CoolerMaster case for my first build. I don't like it. It has a very cheap 'feel', with awful fit and finish. Anyway, the 'tool-less' PCI card holders do not overwhelm me with confidence. I would like to add a screw in the screw hole to secure them. Problem: none of the supplied screws fit the PCI slots. Would anyone know the specific screw size to buy? Many thanks.