this. But not that strong as all of this work ll be later covered by camo, all the chiping, rusting and washing. I started building up highlight with vma german gery with a drop of vma light grey. Aprox ratio was about 5:1. On the second picture you can see the ressult of this method. You dont have to mask everythink by tape and can help your self with piece of plastic card or piece of harder paper(i used empty rolling papers). However i ve tried this kind of highlighting for first time and i quickly noticed mistake i did. If you ll attempt this as well please keep in mind its good to build highlights in one chosen direction, not as i did on second picture. However i left highlights like that as everythink ll be cover by another layers later.