The Sprinter upper cabinet build:
https://sprinter-source.com/forum/showthread.php?t=17527&highlight=orton+upper+cabinets
The Transit upper cabinets were improved in several ways.
https://sprinter-source.com/forum/showpost.php?p=388019&postcount=9
1. Just made a front face out of 80/20 but did not use 80/20 from bottom extrusion back to the van wall. Used a piece of 15/32" plywood as the cabinet bottom. It was bolted to the bottom horizontal extrusion and to the van wall. Both the cabinet bottom and the thermal isolation.
2. The connection to the van roof was changed to provide a thermal barrier. Aluminum angle bolted to the side of each roof rib and then a short piece of 15/32" plywood at each angle down to the upper horizontal extrusion. Plywood hanger provided the thermal barrier. If you bolt the aluminum directly to the van body, I found the aluminum would get close to the van body steel temperature. Seems aluminum is a good conductor.
3. With the slightly lower upper extrusion location I could make the center section of the ceiling flat and not follow the curvature of the roof. The ceiling edges are supported by sitting on top of the extrusion. Only had one bolt at each rib down centerline of van to hold the ceiling material (8mm Macrolux) in place. Ceiling is also removable.
4. Because the plywood cabinet bottom bolted flush to the bottom edge of the bottom horizontal 80/20, the 80/20 acts as a basket retainer. The top edge of the lower 80/20 extrusion is 1 1/2" - 15/32" higher than the top of the plywood cabinet bottom. That is a high enough that the baskets do not fall out. Eliminated the extra wood rail I had on the Sprinter build.
I will post a PDF drawing of the Transit upper cabinets when get to my office this morning. It will be posted at the "orton transit DIY" post on this site.
Suggest we use my Transit build post for further discussion instead of Geek's post.
https://sprinter-source.com/forum/showthread.php?t=37618&highlight=orton+transit