3lbs in a five gallon batch was a little much for my first use of corn. I'd scale back the corn and replace it with rice(if you want it lighter) or 2-row(if you want it fuller). if you're concerned about getting as much sugar as possible out of it, boil a gallon of water, remove from heat, and drop in the maize. Cover and leave it to cook for half an hour. The maize and/or rice should become mush like cream of wheat. Put some cold water in the MLT and dump in the adjuncts and mash as normal. You're using lager yeast, right? go for a low mash temp to keep it dry and crisp.