01
Ask for a representative arrangement
Request a sample board or mockup that includes the proposed colors and variation. A single attractive slate cannot demonstrate a blend. Discuss whether the proportions refer to piece counts or visible area, especially where several widths or sizes are involved. Record the agreed approach with photographs and written notes so the selection can be reproduced during installation.
02
Check the view that matters
Look at the arrangement from a useful viewing distance alongside the building's brick, stone, siding, or trim. Ask how delivered pallets will be mixed to avoid unintended patches of one color. Keep the approved board available through the job. If a material changes, review the revised combination before it reaches the roof rather than approving each replacement color in isolation.