Cool video. After viewing it, I decided to watch this one about the AT-AT Driver's helmet:
http://www.youtube.com/watch?v=RpYkFCVA9Fw
Fascinatingly, the actual colour of the helmet is light grey, NOT white. All the publicity photos of AT-AT Drivers (which include all that have ever been used on Kenner / Hasbro action figure backing cards) are over-exposed, making the grey appear to be white. This means every single AT-AT Driver action figure ever made actually has the wrong colour helmet!
I have no idea how much impact this has on ESBR, as the AT-AT Drivers' helmet colour choice is quite naturally Ady's, but if they should happen to appear to be more grey than you remember in the final version of ESBR, don't be surprised :-)