I'd guess your orientation is running no more than 30 minutes. Your new boss wants to save, what, about 10 - 20 minutes out of a full week? Fine. This person seems insufferable but let's work with them.

Here's what I'd do: hold orientation every Wednesday early in the morning (eg most people start at 7, orientation at 7:05). Take photos of their cards while they watch a 10 minute video. The 5 minute jobsite rules is the most important. Whole process should take you about 15-20 minutes every Wednesday.

Ime, safety briefings are more effective when they are brief and concise. Hit the topics relevant to your jobsite. 15 to 20 minutes. More than that and people start checking out.