Adult mantis will not molt anymore. You were being given wrong information. In my case, I started keeping mantis with 5 L1 Asian mantis. Now I have 5 orchid mantis, 1 devil's flower mantis, 5 Chinese mantis, 6 ghost mantis, 5 dead leaf mantis, 7 Indian flower mantis and 5 spiny flower mantis.
The best way is to get a few at the same time. They are fragile animals, especially the first two instars so you might want to get more just in case you made mistakes.
The best way is to get a few at the same time. They are fragile animals, especially the first two instars so you might want to get more just in case you made mistakes.