Six pounds of chocolate malt?! Am I reading that correctly? That will give you a high finish gravity and make for a very sweet beer, even without considering the unfermentables in the LME.
If the final is too sweet, you have two choices to dry it out: Alpha amylase concentrate or alpha-galactosidase (Beano).
The downside of Beano? You have to heat the beer to de-nature it once you reach the desired dryness. Otherwise it will continue breaking down the sugars until there is nothing left. You end up with a high ABV, low-carb beer with almost no mouthfeel.
Alpha amylase concentrate will leave some sweetness and mouthfeel.