Louise,
Your institution's cap of 25 students is lower than many I have encountered, but research is emerging to support it. My experience finds 30 students per section is a popular number among institutions, but it may be a little high for optimal student-student interactivity. Student numbers of 15-20 per section are likely to be optimal for many technical classess. Certainly, these would be desired by the instructors. Thank you for your contribution.
