Screen door doggie flap bracket

Using a standard vinyl screen door with 4 slats on the bottom half, I removed the two center slats. Used one of these to go flush against one of the remaining two, and cut the other to provide a second cross bar to install the bracket. This bracket is for a x-large Idea Pet Products replacement flap. Each bracket is 19 cm so you need two to reach across the 38 cm top of the flap. Slide the flap into the groove and screw the bracket onto the new cross piece you installed earlier. Cut out th