When considering the installation of horizontal sliding doors, what detail regarding door panel alignment should be prioritized?

Prioritizing the detail of clearing the sill when installing horizontal sliding doors is essential to ensure proper functionality and safety. The sill is the bottom part of the door frame that the sliding doors move over. Ensuring that the doors clear the sill allows for smooth operation without obstruction, which can cause wear on the doors or even lead to malfunction.

If the doors do not clear the sill properly, they may become stuck or misaligned, which could create operational issues or even pose a safety hazard. In a passenger elevator setting, where the movement of doors is critical for efficient and secure passenger transit, this detail cannot be overlooked.

The other options do not directly influence the operational integrity of the door system in the same way that proper clearance does. Color matching and panel size variation may have aesthetic or installation aspects, while safety sensor placement is indeed important but pertains more to safety features rather than the door's ability to function correctly with respect to the sill. Thus, ensuring that doors clear the sill is fundamental for a reliable and safe installation.