Completed an upper grille block this weekend. I removed the grille and traced a newspaper template from the grille trim ring, then cut it out of 0.020 aluminum sheet with mounting tabs that extend past the mounting screw holes.
https://www.dropbox.com/s/dglt6im5juazkhi/IMG_3181.JPG
And a quick comparison to a twin..
https://www.dropbox.com/s/jjgi1fmp1b...%20Comparo.JPG