Start with the exact product
Ask for literature that identifies the exact range and thickness being quoted. A catalogue covering several systems does not confirm which values apply to the proposed item.
Match documents to the project
Compare the architectural use, exposure, height, support, openings and finish with the conditions covered by the manufacturer. Record questions rather than assuming a generic claim applies.
Read the commercial scope
The quotation should distinguish material, transport, unloading, frame, fixings, labour, joints, scaffolding, finish, tax and exclusions.