I just wanted to add a few things to this thread as suggestions/alternatives for other people who will be following this awesome tutorial.
1) I made two of these tubs and for the life of me, I could NOT cut through that thick plastic with a scorer, an Exacto knife or even a razor box cutter. I ended up having to use a soldering gun to melt through the plastic. That plastic was a lot thicker than I thought it would be! I'd actually recommend skipping the scorer and just using a soldering gun because it was definitely easier and faster.
2) Instead of using hot glue, I used RV silicone to adhere the screen to the tub. I chose this method because I didn't want to risk burning myself with the glue, haha! To make sure the screen was taut, I siliconed the bottom of the screen first and let it dry, and then I did the sides and the top. It's held up great so far.