This design-based research (DBR) project aimed to develop apt in-class and out-of-class teacher facilitation strategies to be employed in a pedagogic integration of flipped learning and social enquiry learning, viz., FIBER (Flipped Issue-Based Enquiry Ride), with respect to upper-, average-, and lower-academic classrooms. The research was conducted in the formal learning and teaching context of senior secondary social humanities education in Hong Kong, involving nine teachers (from nine different schools at three different academic bands) and their Secondary-5 (Grade-11) classes (with a total of 610 students) in two consecutive school years. Apart from delineating the evidence-based teacher facilitation practices that we designed, enacted and evaluated in the DBR process, this paper also discusses the principles that we derived in accordance with these practices. The present work provides both researchers and educators with new insights into developing adequate teacher facilitation strategies when adopting flipped learning in social humanities education and upon different formal schooling settings.