I'm new to the community but the overall wisdom suggests that you should, if possible, save releasing on HN till you have the MVP. It's a good gauge for measuring the interest but if you launch after you have the MVP, you could legit get more traction, sign-ups, paying leads and actionable feedback. Because I'm not quite sure if you launch the same thing after you have the MVP, it would have the same reception since it was already launched once. Obviously, let me know if I'm wrong, because it's what I'm under the impression because even I'm waiting to release a personal project once it's done.