Hi, I am going to use pastillage and how much does it shrink after it dries?? 

Amine did not shrink

AThanks doing a crib cake and wanted to know if I have to cut a few cm extra. Now I can just go by cake length

no but if it was me i'd make extra pieces because it is brittle and can crack on you -- how big is your crib? would gum paste or heavily cornstarched/tylosed fondant or royal icing work? is it real big or something? i've only worked with pastillage a bit

its about 9 inch by 7 inch crib cake. The  fondant with tylose takes atleast 2-3 days to dry. I do not have that much time since it is short notice. so left with pastillage or chocolate melts 

good luck -- would love to see a photo