Pick people who already said something kind in writing. Ask one question (“What changed after we worked together?”). Give them a 60-second target. Send a personal Request, not a newsletter. Let them record on the phone in the browser.
Do not require a polished studio. Approve in an inbox. Put one video above the fold on a sales page and the rest on a Wall of Love. Qintr is one way to run that loop: in-browser recording, Requests tracking, video widgets. You can still use a generic form tool — the process matters more than the logo — but the recorder has to be in the link you send.