How do you onboard beta-testers/early-access users?

I've seen a few different approaches to handling early-access users and beta testers, ranging from totally hands-off to very hands-on.

I've seen some apps where you can just sign up as a beta user with no screening or hand-holding process.

Then I've seen some apps that require filling out a form and waiting on a list. The form is used to qualify users and get feedback, and the waiting list is used to control the number of early users.

And I've seen the concierge manual-onboarding approach popularized by Superhuman in which founders manually onboard users usually over a video conference.

Anyone have experience, advice or recommendations with these approaches?

Thanks!