Unless you are doing something truly unusual or something that requires a lot of investment in time and capital, you should just tell as many people as you know about it and see what happens and reiterate based on feedback.

Consider some YC companies that are still fine-tuning their product. They've been reviewed by the likes of pg and co and had the benefit of their advice for 3 months as well as the benefit of experience from the large pool of YC alumni. But even they need to fine tune based on what the larger market thinks.