I would hold at least half of them to sell as sexed pairs. With vents this would only take about 5-7 months. The others i would sell at about 3 months. I think alot of people are selling frogs to small, especially if shipping thumbs i would wait 2- 3 months. I know someone who had some retiics shipped to them and they still had tails, this is unbelievable and should never happen. All the retics looked really bad and probably died or will die, and at least all be runts. Since this is your first foray into selling them, why not wait as long as possible. It will give you enough time to make sure they are developing right, and give you stronger stock to ship.