Approved Vendor : Total Composites
One thing to consider with the 8020 pieces running horizontally across the roof:
when there is a large temperature difference between the outside and inside, the roof panel will bow downwards.
I don't know if it is better to let it flex or better to resist the bowing.
The cabinet you are building looks close to a wall so maybe the effect will be less dramatic.
Expansion/contraction is certainly something to be aware off. I'm personally not a big fan of metal interiors. Adds a hole bunch of complexity.