Although the Rustoleum 2X gray primer is far too light for the German Dunkelgrau, it is a primer I have used often on 1/16 RC tanks and other models. But for German Panzers the primer was reddish: among the Rustoleum line, the 2X red primer is a great choice from my experience. On the real WWII Panzers, Dunkegrau (or Dunkegelb) went over the reddish primer.
Herr Doktor. Professor,
CEO, CFO Golden Prairie Railroad
"You need three tracks."