If you’re in the situation where you need to share some technical (or “heavy”) information with your audience then the Tell Tell Tell structure is going to be most appropriate for you to use. The premise behind the Tell Tell Tell structure is continuous reinforcement. It’s unreasonable to expect your audience to understand something detailed the first time you share the information with them. If your audience was reading a book to gain the information they can re-read something they don’t understand. Your audience doesn’t have that luxury.
The opening of your speech or presentation is to tell your audience what you are going to tell them, the body of your speech is to tell them what it is you want to share with them, before you close by reminding them what it is you’ve told them. This provides them with the opportunity to understand something which may have escaped them the first time you said it.