I've got an old XC bike, niner air 9 with reba RL that I've been running Kenda Small Block's on and have been very happy with them. Its time for new tires and saw that Schwalbe hs a new tire thats got a similar tread. I'm likely going to get another set of kenda small blocks because they match up well with the local trail I mostly ride that bike on but figured I'd see what tires people recommended for a trail that is mostly smooth hardpack with a little bit of loose sand. I think the width I was using was 2.1" and the frame wont' go much wider.
Also I have a YT jeffsy with 2.5" onza ibex tires that I ride on more technical trails so this bike really only gets used on smoother XC trails.
I'm a fan of Maxxis Ikons for XC. They have a somewhat similar tread pattern to the small blocks but I think Maxxis uses a better rubber compound (Maxxspeed I think it's called). Also, in my experience, they seal up tubeless far more easily and are lighter for the same amount of flat protection.
I'm running the Rocket Ron in the Pacestar compound. I really like them so far. They are far lighter and roll faster than the S-Works Ground Control/Fast Trak combo I came from. Grip is pretty much on par. You can find them at pretty reasonable prices in the UK or mainland Europe.
The SB8 isn't that "fast" of a tire despite being an XC tire.
I Ride the new Bontrager XR1 tubeless for hardpack trails. Its fantastic. Great rolling, predictable corner traction. The Tubeless versions are a great weight. My favorite tire by far. I ride the 2.2 width at about 22 - 24 psi i'm 165lbs