I do paid beta for people who haven’t been satisfied with the free ones they’ve been able to find, and I’ve created a questionnaire much like yours. It’s good to know of a few other resources for them, though, so I can refer people if they would rather have free betas, or a mix of both. The feedback I keep hearing is that it’s so hard to find reliable ones who give decent, useful feedback, but once they do, they don’t let them go.