Dry hop immediately before serving, in the keg if you've got it.
Use a dry hop bag and make sure you can pull the bag when the intended intensity is reached, or if you detect the slightest hint of grass. It doesn't take long with a delicate lager!
I actually prefer to dry hop in the kegorator. I know several pro brewers have stated otherwise, but I think I extract less grassy/vegetal flavors on the cold side. Its easy to get a daily sample when its on tap!
I used an ounce of Moteuka in a Pils recently. Sublime!