If you want a lighter, crisper mouth feel, I would probably mash around 148 or so, but don't go too high in the alpha amylase range-that will give your beer more body because of the unfermentable sugars left behind. For the whiskey part, I would soak the chips in whiskey for about 1-2 months and add those to the secondary when it comes time. You will probably have to use a bucket to do this, so watch out for oxidation from oxygen permeation through the plastic, not unless you have a barrel.