Great question. The ordering window for this project has passed, but I will be posting overstock boxes for the past Crate Club projects in my Etsy shop soon. 👍
Try it on a scrap of cedar. The kind of wood and burner you use will make the temperature you need vary (sometimes in a big way). I would start at whatever is a medium low temp for your burner and work your way up in the scrap until you get the look you want