I don't think it really matters, as long as you give the 1 lb. of sugar time to dissolve completely in the boil ... No matter what, I don't believe the sugar will be evaporated no matter how long you boil.
Primary: Empty (planning another Oatmeal Stout)
Secondary1: Strawberry Alarm Clock v3.0 (Strawberry Blonde Ale)
Bottled: AHS 20th Anniversary Belgian Wit, Oast House Oatmeal Stout