Deflasking-when?

[Connie Star]

I returned from a vacation in Costa Rica a few days ago and came thru Miami with a small flask of "Baby Orchids"- Cattleya dowiana. They were sealed, "in vitro" and sterile and I had no problem getting thru customs and agricultural inspection.
Now I need to know when to de-flask them. The directions say when they are 5 cm high (2") and they are at about 4cm. The agar looks good, so I think I should wait awhile? They look very healthy. I could use some advice on this.
I plan to put them in a "compot" with NZ spagnum moss, then put a ventilated plastic bag over them and keep them out of direct sunlight.
This is a fun experiment for me before I try ordering hybrid flasks in the future.