Honestly, this rather shows me that he's not as good as other people who make racks. Chris doesn't use any wood to slide stuff over because he recesses his heat tape inside the racks so the tubs slide right over, this also helps you get the inside of the tub at the proper temp. That big gap causes more of a heat loss so you'll have to turn the thermostat up higher to get the appropriate temps and I can almost guarantee you that the tape you're using will lose it's stickiness.