1. Fit the detailed couplers, but include one functional one per Sprinter. OR
2. Fit detailed couplers, and sell as an alternative the functional one. OR
3. Fit detailed, include a functional, and have both purchasable as spares.
Options 1+2 cater for accurate detail single unit running, and functional multiple unit running at two units only. Option 3 allows those wanting multiple unit running above two units to purchase the couplers to satisfy that .
Just my thoughts.