Sorry I am a bit late on this. Here is what you will need
I insulated the inside of the tote with double bubble aluminum. It’s pretty cheap at home depot. I also had a wooden dowel I cut in half and screwed into some scrap 2x4. This each dowel will hold 3 spools, and I can slide another two spools on the sides. The heater block is mounted on the underside of the lid, with some scrap wood acting as a mounting block and providing an air gap.
Adhere the double bubble to the inside of the plastic tote with 3m spray adhesive. Make sure to dot the underside of the lid too!
I also printed out a small enclosure for the PID controller and relay.
Looks like it’s a bit more expensive to make now, but still just as effective as one you can buy, and can fit way more!