Glad you found it!
Regarding your question about a reasonable size for course sites, in case it’s helpful I can tell you a little bit about our experience with the OpenLab at City Tech.
We limit individual file uploads to 10MB, and set site quotas at 300MB. We’ve found this is more than enough in most cases, and if necessary, exceptions can be made on an individual basis (in Network Admin > Sites > search for site and Edit > Settings).
We also try to make OpenLab members aware of size limits, how to optimize large files (e.g. reduce large images before uploading, convert pptx to pdf), and best practices for sharing large files, including hosting externally and embedding or linking out whenever possible.