Greetings!
I don’t know if dimensions really matter that much anyway… My advice is to never buy anything until you actually have the van, unless it’s totally portable, or small enough that you it’ll fit somewhere.
If it’s a cargo van, you can’t really plan for windows, floors, walls, or ceilings until you actually have it and can eyeball it yourself. Even vans of the same year, make & model can vary significantly.
Cheers!
"Be the reason someone smiles today!" ~ Van_Dweller