Basically white-ish grey. I used flat white and camoflage grey to get it look right. Saw it in person too in Cologne and its much "whiter" than ppl think it is. Most builders paint their Star Destroyers grey which is not hat was used at the original.
The pattern is very subtle and slightly hidden under a coat of white/camo grey. And there is very much pencil work on the whole model. Every scribed line + lines that where just drawn.
Here is a pic of my version of it:
View attachment 709334
Did you actually go over the lines with a pencil?
Looks great...but is the color not a little bit too "white"?:unsure