What is your experience, are people willing to talk for extended time with strangers about their businesses?
They will definitely know ballpark numbers about everything, that they might be willing to share.
Show that you value their time by setting the space upfront, and when you're 10 minutes away, tell them "We have 10 minutes left, and I want to respect your time...". They'll decide to keep rambling or not.
Re: numbers, you can also preface with "I'm not looking to know anything confidential, but since I don't know your industry, as we talk, it would be great to have numbers with some context.
Here is my verbatim intro for learning more about cities+construction:
"Hi! I'm a technologist who left the tech world, and I'm focusing on how I can help cities. Particularly helping cities make better decisions with Data.
To prevent building something that doesn't help cities, I'm listening to key people in your space and understanding the problems they face. I'd really like to get an understanding of your role and the issues you face, particularly around the permitting process, and code compliance.
The conversation is less than an hour, and I can meet you in person, or over the phone. The questions are lightweight, no quizzes here. :)"
- nic
It is a slow process, but when you're in that "listening mode", you get to hear about their (and their industry's) day-to-day challenges, problems that they encounter, and their current answers to those problems. They might not give you their whole financial records, but the insight you get is far better than what you'd end up with after searching the Internet for an afternoon.