Lager it as long as you can wait, preferably at least 2-3 months at about 30 degrees. I made a lager that was 18 percent and lagered it for 1.5 years at 30 degrees and it turned out great-very smooth, no alcohol bite. For me, fermentation is around 45 degrees for about 2-3 weeks with a HUGE starter being pitched (about 2/3 gallon for a normal strength beer). Good to see you aren't in a hurry, you will be rewarded if you wait as long as possible. If I made a doppelbock now, I wouldn't drink it until the end of Jan or early Feb of 2009. It would be plenty smooth by then!