I think that some museum's team (as NHM) uses this method.
Yes, that was exactly the way we did it when I was collecting microleps with NHM people visiting me here. We used to catch the moths live in small plastic tubes with screw-on lids then just pop them into a cloth bag which would go into the freezer when we got back home.
The next day, before going out trapping again, the moths would be removed from the freezer, allowed to defrost and then spread straight into small plastic boxes with plastazote in the bottom. We used a micro-pin through the thorax, then pinned the moth upright on the plastazote and used a needle to spread the wings out on either side. Almost always the wings would just sit in place without any need to hold them there, and the moths would dry out very quickly as they are so small.
This kind Adam (here setting pins removed and label put under specimen), a box with some Choreutid I bred in Cameroun . The specimens were set immediately after emergence in this box.
s'il n'y pas de solution c'est qu'il n'y a pas de problème ! akuna matata ....
Yes, that's exactly the sort of box. We didn't use any setting pins, although sometimes the occasional specimen would need a micropin against a wing margin to stop it moving. Usually the pressure of the wings on the plastazote was enough to stop them from moving once they had been opened out with a setting needle. After filling a proportion of the box we would draw a line around the edge of the specimens and include a single temporary data label for all of them.
It is worth noting that micropins are VERY dangerous and should be handled with care. If you drop them on the floor and someone treads on them the pins are so thin they might not even notice, and they can work their way deep inside someone's body.