A single palatal strap is most suitable for small span Class III modification 1 located posteriorly because it provides adequate rigidity and support with minimum bulk. It effectively connects the limited edentulous area, distributing masticatory forces while maintaining patient comfort. For small posterior spaces, it offers sufficient strength without the need for extensive palatal coverage seen in other designs, preventing interference with speech and tongue movement. Larger spaces or anterior edentulous areas require broader straps for better load distribution and stability. Thus, the single palatal strap is ideal for small, localized posterior edentulous spans typical of Class III modification 1.

Reference: Prosthodontics, Shigli, 3rd Edition.