Oh damn. I never thought about adding the extra two pieces. That's good. Thanks.

Just to add some extra detail for others. The router bits have bearings that ride on the template. The bearings prevent you from cutting farther into your final piece but cuts everything else out.

I have a small table router. I find that holding the router by hand results in some wobbling and therefore imperfect cuts. Because of that I can't clamp the pieces together. So, I bought some industrial double sided tape that works extremely well.

So I have a rough idea of how I'm going to cut the corners I want, I mainly was looking for the type of name of the corner/edge so when I went to my local woodcrafting store it would be easier to ask what tools/bits I need. Or just explain to them what I'm doing, the guys that work there are older gentlemen that love to talk about tools and projects so they are always genuinely interested in what people are making.

Thanks for the advice though, I hadn't originally thought of additional rails/fence, most of my router work has been "let me route this edge and make it look nice" or "I can recess the wire for this bird feeder with a rabbet" I've never thought about using it to cut off a big corner of wood before so I may have to try it out on some scrap wood and see how it goes.