OP - your unloaded weight is no big deal. I'm close and ride 25c GP4000s on my Roubaix, Ultremos on another fast bike. No issues, great ride.
For additional flat protection and weight management on my Tricross with bags on the rear..I subsitute a 25c Gatorskin on the back. Since my flats always seem to happen in the rear, the combo of GP4000s front and Gtskin rear have worked out to be a good compromise between speed, handling, stiffness under weight and durability.