Some thoughts...
- Free users are more like followers than paid users. Need to learn what paid users want. It is a very important distinction.
- When you say you chose best performing freebies, is that defined from use, your perspective, customer discovery???
- What pain are you solving with the free?
- What pain you solving with the premium version?
- Have you created a vitamin or a pain killer?

Let me know if you want to learn how to do great customer discovery and scale.