One way to get the pattern is to tape strips of paper (together) to the inside of the plexi and than cleco it in place on the fuselage every 4th hole. Use a sharp pointed tool to punch the line of screw holes in the paper, now remove the paper and draw the final shape of the strip using your defined screw holes as a reference. It might be best to break up the strip into 2 or 3 segments for best fit. Now you have templates for the strips.
One treatment you could do to hide the strips from outside view is paint the plexi along the inside (similar to the treatment on your car's windshield) edge flat black, as well the strip side that faces the plexi. Makes for a nice neat finished look.