Nice design and install pwelco, reminds me of the rear speakers in a TLC Icon.
PDF? I don't need no steenkin' PDF. Guys, the OP has shown you how to do it - just grab some cardboard and a sharpie and go make yourselves a template.
WHoa, whoa, whoa.... slow down with those instructions...
1. Grab some cardboard, is it a specific kind of cardboard, or the kind hobos use for shelter?
2. Grab a sharpie, how sharp does it have to be?
3. Make myself a template? What kind of fun is that? There is already one in a soon to be pdf!