Well, as you guys already know, CAAD uses a 6 series alu which is easier to manipulate, but the alloy itself is not as strong as 7 series, while we use 7046, a more advanced 7 series alloy. It's a bit more maleable than 7075 but has superb strength. We have built a sub-1000g frame using 7046 in size M, but for the Saker, we deliberately kept it at 12XX grams for a medium in order to get the right stiffness that racers love out of these alu frames. The down tube is slightly over 50mm, and ovalized at the right spots... The wall thickness also went up slightly to reduce denting.
The other special thing is the welding technique where the weld is not evenly spread across the joint, ie., when a 1.1mm walled tube joins a 1.6mm walled tube, the weld would be split 4:6 (or 3:7) at the joint with more material over the thinner section. This effectively makes the triple butted tube a quadruple butted one, one might say. See, the reality of alu butted tubing is that you can't really perfectly butt the tube for a particular frame size, as they are butted in bulk and then with the right length chopped off for a specific frame size... so there is a bit of guess work there, especially with the seat tube where you could have a 54cm tube for a size L but a 41cm for a size XS. Theoretically it's possilbe to butt a tube that's ideal for that particular frame size and geometry, but it would be ridiculously expensive. So this is a pretty cool thing to have.