Historically speaking for the past few years, the winners have been who has the most 'found first' eggs. I can understand why you might have thought differently, because without the puzzle eggs, it is possible for a member to reach the egg maximum before anyone else.
It wouldn't be fair for us to go by 'whoever reaches egg maximum first', because it would always boil down to only the final unsolved egg being relevant (given that everyone helps each other out privately), and whoever had a favorable timezone for the last batch of eggs (or forced themselves to stay awake).
"First person to find the most eggs" is leftover wording from when we used to have the Golden Egg purchaseable in the shop. We agree that our word choice has not been very clear and open to multiple interpretations - which is why we struggled between the three winners this year, and are committed to ironing it out before next year's hunt.