I've been riding this tire combination for the past 6 months or so, the Specialized S-Works Fast Trak 29x2.0 up front, and the S-Works Renegade 29x1.9 in back. They're both really fast and very light weight. The Fast Trak has a lot of grip especially in looser conditions. I can really lean into a turn much better than the Renegade. It comes in at about 520 grams, which is very respectable. I run both tires tubeless at around 23-24 psi.
With the upcoming race season I'm contemplating running the even lighter and faster rolling Renegade 1.8" tires. They have low rolling resistance, but require a bit more skill and finesse on loose and technical terrain. That's about a 1/4 pound of rotation weight savings, which is substantial for a race bike. I'll wait for dryer conditions before I pull the trigger.