Napoleonic cavalry questions

Just wondering if anybody knows-

1. Baron Marbot emphasizes that French cuirassiers had a significant advantage over their Austrian (and other) counterparts because they had a backplate. So why didn't the others have one? Was it a cost issue?
2. Do we have accounts illustrating exactly how carabiniers and chasseurs-au-cheval would use their guns in combat?
3. Same for lancers and uhlans, are there specific diagrams or discussions about how they operate differently with their unique equipment? thank you anybody who can answer!