Grab my butt ......... plate template!
You can just use this jpeg and insert it into a document and scale to size. It's designed to be printed out on 11"x17" paper but you can always divide the jpeg into two "cheeks" :lol and just tape the two printed pcs later.
It's a simple butt plate template to be sure - but grab it anyway!
p.s. It will marry up with the large cod pcs I've sold or you can simply add or remove width to the ends to match any cod.