I find that people who are honest will engage with you. You could start asking questions by email. If they're cagey, uninterested or incompetent, you may or may not want to give them your business. You can ask them about CAD design, bottom bracket selection, fork clearances, the grade of carbon used, where and why, for example. That would show you know what you're talking about and i'd be careful if they can't / refuse to answer.
