Promoting evidence-based assessment practices at scale across different disciplines is a challenge. Feedback, although powerful for affecting change in students, is not always adequately implemented. An assessment framework based on strong formative feedback and other evidence-based educational practices was designed to give capstone project students an authentic learning experience, and was deployed across all our Software Engineering capstone project units involving more than 700 students and app. 30 academic staff members per teaching period. The scale of our setting raised the question about consistent and faithful implementation of the framework and its guiding principles, essential for achieving the assessment framework outcomes and equitability for students. In this study, we explore the challenges of implementing assessment practice at scale and report on our findings and support strategies in order to facilitate consistent engagement of teaching staff. The findings of our study form the building blocks of a decision-making framework to guide the implementation of ongoing pedagogical innovations at scale.