Products Business Model Support
Who are your client? Do you have paying consumers right now? Who are they, and how to they use their product?
The problem I see with you product is that you can't make people pay if they only need a onetime extraction. And they won't pay only to test if it works or not. If they pay and it doesn't work, you'll be in a lot of trouble.
So, who are the people who will pay? To me, I think they are businesses that needs to extract data regularly from PDFs that are always the same canvas.
The first think you should do is figure out that, and then you'll be able to choose the correct strategy.