Mounting and Rat Bites

So, I just finished mounting my obit. Does Letramax make cutting easier? I bought all the fancy toys: Exacto knife, straight edge, mat cutter, rubber cutting board, high-in-a-can Super 77 and non-Letramax matte board paper stuff. I cleared a space on the table, put on some relaxing music and starting cutting. I thought it would be so much fun. Unfortunately the mat cutter is designed for a right-handed person--I am a lefty. Adjusting the cutter involves a Phillips-head screwdriver, which I have...somewhere.

After giving up on making the cutter lefty-friendly, I continued cutting. After a few close calls involving my dining table, I moved the show to the floor. I did get the board cut, but it's not pretty. It looks like a rat gnawed off one side of the board. And somehow after carefully measuring and marking the board, it's a 1/2 in. larger on two sides than the other sides. The larger sides are also the rat sides.

Now, I know I should try to even the sides...but considering what it took to get the uneven rat board, I'm quitting while I'm still slightly ahead.