Dude, Awesome freaking helmet!

It's coming out super clean! I hope my helmet comes out like yours.
I have a few questions,
1) How did you get the lines around the ear and the one going up (Pic #2)? The ones that show depth to the helmet.
2) How did you bondo the ear area? (If even Bondo'd)
3) How did you make the circuit board looking thing?
4) How are you sanding this? Mouse/Palm Sander? By hand? Also, What grit(s) sandpaper are you using?
5) Roughly, How many layers of Bondo did you apply?
Sorry for all the questions, I just really want to make mine look like the real thing.
Can you take a look @
my Daft punk helmet and give me suggestions/tips or w/e?
Please and Thank you.