The proliferation of Generative AI (GenAI) has created a need for effective tools and strategies to teach young people how to use and think about these technologies. This paper presents work in progress extending a successful trial of an AI-focused constructionist learning package, which includes a proprietary GenAI tool, lesson plans, and supplementary teaching resources. To explore the scalability of this approach, we interviewed education practitioners. In these discussions they reflected on findings from the initial trial to identify potential challenges and opportunities for broader implementation. From these insights, we propose a set of design heuristics for designing scalable GenAI education platforms.