It's always best to take the nose to eye measurement before removing it from the skull. It will never be as acurate as it is at that time. That being said I have extra change out heads laying around that I will stuff into the cape to fill it out and then take the measurement that way. If you don't have something like that at your disposal then some waded up newspaper or a chunk of foam carved down to simulate the skull can be used. If you lay it flat without filling the void your measurement can be quite a ways off. It's always best do do this AFTER you have it tanned and rehydrated. Hope this helps.