How do I check a coach's student results when nobody will show me a file?

I'd like to end up with the one that actually works, so I'm doing diligence on two programs before I spend $9,000. Both have testimonial pages. Both have a number on the homepage, one says students have done over $400 million in transactions and the other says 1,200 deals closed. Neither will tell me the denominator. I asked one of them directly how many people enrolled in the last cohort and how many bought a property within twelve months, and got told they don't share that because results vary by student effort.

What I've managed to verify on my own: both founders own property, which I confirmed in county records for the counties where sale prices are public, though a couple of the states they operate in don't publish price at all so I hit a wall there. Neither has anything I'd call a complaint pattern that I can find.

What's the actual set of questions that gets a real answer here? I don't need a guarantee, I need to know whether the median enrolled person does anything at all, and I can't find a way to ask that doesn't get deflected into effort talk.