Installed Milspec dzus fasteners aroiund perimeter of firewall after using the supplied templates to drill out the locations and prepaing and priming the fastener strips. Drilled out the cowls 7/16" at the fastener locations (and the lower cowl to 1/2" where the top fasteners overlap the upper cowl) and installed the metal grommets and snap rings. Then I inserted the male fasteners and put the cowlings on the airframe to adjust the fasteners to their final depth.
