Remember though - simply adding sugar will not dry it out. The idea is to remove some malt from the bill, and replace it - SG point for SG point with the sugar. If you just take a 1.050 beer, and add a pound on top of the existing malt bill you will only get more alcohol, not a lower FG.
I have a bitter I am brewing now using the NB Marris Otter syrup. I know this doesn't ferment as much as I could get with a low mash temp, so I removed 800g of the syrup and replaced with with corn sugar.