I have gone both routes with three different helmets and here's my two cents.
The layered look is phenominal, IF you can do it correctly. Right now, my DP 96, which is beat to crap is layered. It's nice because if you can chip the paint away just right, you can see the "depth" of the layering. However, if done poorly (like my Dp 96) it just looks like a piece of crap.
As far as the silver spray paint goes, I have not had any problems with the Krylon Original Chrome (#1810) as long as you have primed the area first.
Now, for the DP 95 I have, I decided to paint the silver on with a Testors Silver Paint Pen. As long as you "dab" your areas in (as oppossed to smearing it), it turns out pretty good.
I am basing my paint loosely on the DP Deluxe and my apologies, again, for the pics. Stupid broken digital camera.