PDF to only download, not open

I've chosen Tips and tricks, hopefully it means this will be an article/explanation instead of a question. I had the opposite problem to [[PDF files should not download, only open in browser]] and was happy to find out in the OP attachment that the action for each file-types could be changed. I didn't want my bandwidth strain of having to download PDF twice anymore (especially ones with many images). I was going to leave the following on a comment of the other thread but it was locked.