1) Is the yoke for the handle bars on the V20C carbon or aluminum? Was looking at purchasing some aero bars and they say that the fastening device has to be carbon as well.
2) I still have not found a concrete answer to the brake lever question of "if the lever is good for rim brakes then it should work for mechanical disc brakes as well".....right?
1. The V20c slider is carbon, including where it cradles the bars, but the clamps that wrap around the other side of the bars are aluminum. So the most accurate answer to this question is, half carbon, half aluminum. Hand position with these bikes can be pretty particular, and can vary from rider to rider. If the bars that I use on my V20c and S30, set to where my hands feel most comfortable, were aero bars with flattened, winged tops, the wings would be nearly vertical, making them the opposite of "aero," and possibly obstructing my view a tiny bit. You might want to start with the bars that come with the frame kit, see how you like them, see where your hands like to be, and go from there. There have also been several discussions over the years about bar choice here on the forum. Search "Handlebar options v20c" as a start if you want to see what some have said on the subject.
2. Mechanical disc brake calipers come in "long throw" and "short throw" versions. Road bike style brake levers tend to be short throw, while mountain bike brake levers are often long throw. Many brands offer both types, and the trick is knowing if you have long throw or short throw levers. For example, TRP makes the Spyre and the Spyke. They are basically the same brake caliper by design, but the Spyre works for road levers while the Spyke is meant for mountain bike (or flatbar) levers. Avid specifies "Road" (short throw) or "Mtn" (long throw). The Growtacs only come in short throw, so they are best suited for road style levers.
I hope this helps. Happy building!