If you follow OMH Agency founder Tiffany Youngren's "Winning Interview" framework, you will have a testimonial from each guest you interview.
Capture those testimonials and enter them into the Custom Values.
Settings > Custom Values
There are 12 testimonial Custom Values that are sprinkled throughout the invitation emails in Stages 1-3 to help increase your conversion rate.
Add your testimonials into those fields, from 1-12, and as you do, they will immediately appear at the bottom of your Stage 1-3 emails.