From my use of FOG for the short about of time. Few key important parts for making capturing image go faster and deploying. I know when I skip these steps, FOG will capture much more. Which takes longer.
Step one - Turn off hibernate mode and delete the file.
Step two - turn off swap file and delete the file
Step three - Delete all cache files
Step four - defrag the drive
Step five - turn on hibernate and swap
Step six - capture the image. I am running raid 10 with 10 gig network. Windows 10 fully updated and ready to work takes about 45 minutes. To deploy takes about 5 minutes. My image size is about 50 gb.