anyone actually finding someone's email successfully?

Author pages. If the person has ever written for the company blog or a trade site, the bio at the bottom often has an email or at least a handle you can work from. Conference speaker pages are similar.

inherited the same mess last year. the bit i would add to the usual pattern-guessing is that on small sites the address is often already on the page and just not linked - the privacy policy, the terms page and the domain registration details carry a contact address more reliably than the contact page does. and if it is a one-person business, the form on their site really does land in their inbox. the unglamorous route is usually faster than the clever one.