I originally started with 100 lead free trial since I wanted people to convert one and then sign up for 1,000 or more. But it ended up being costly and not everyone converted their 100. So I switched it to 25 and communicated that the goal wasn't to convert a lead in the free trial but just show the quality of the data we could provide.

I think that's an important an often overlooked idea: you really need to help your customer think about how to try your product. Guide them along that process based on what you've seen work in the past. Don't let them figure it out and evaluate on their own.