If you want to start making these even faster and more uniform, I'd suggest getting a router table (or building one they can be had for not too much money) and get a pattern bit for it, and make wood patterns of the items you need. Then you just use some double sided tape, tape the pattern to the plastic, and run it around the router table for a nice clean and perfect shape every time.
Would work for the case guard as well. Might be other ways? But this is the easiest I can come up with from what I know and have used lol.