Nice. Did it fold away or roll away?
Thanks for adding the link. I skimmed the first and last of it and found this in the last post. I'd missed it before.
Patent US6959958 - Aerodynamic combination for improved base drag reduction - Google Patents
It would appear that a box or detached plate perimeter should fall on the Template line. Other experimenters tested a detached plate with the middle 50% removed.
I interpret the single data point as a mod to their best performing candidate.