01
Use the same comparison headings
List the actual slate, complete assembly weight information, applicable slope limits, substrate requirements, installation instructions, flashing interfaces, and supporting documentation. Ask the project team to identify which differences matter for the building. Do not reduce the decision to material appearance or a single weight figure without considering the rest of the roof.
02
Include the ownership experience
Compare how individual pieces are serviced, what spare components are needed, and who can perform the work locally. Ask how future sourcing is handled without assuming indefinite availability. Keep the comparison tied to documented facts and mark unanswered questions. The best choice is the system that meets the project's requirements with a clear installation and maintenance plan, rather than the one described by the broadest claims.