Group by developmental stage, not convenience
Grades 6-8 and 9-12 should hear different versions. Combining a sixth grader with a senior forces the content toward the middle, where it serves neither.
Two back-to-back sessions on the same day is usually the most efficient structure.
Room, sound and sightlines
A gym works if the sound system is intelligible from the back row. Seat students facing the presenter rather than spread along two sides, and keep staff distributed through the audience.
Plan the follow-up before the date
Decide in advance who runs the quiz, when advisory covers it, and how administration will confirm publicly that reports were acted on. Booking the speaker is the easy part.
Want this covered live with your students? Review the assembly program or check available dates.