Arcane, I may be misunderstanding your post but it sounds like you want to pick one thread to use across the board. Thread is like any other tool, the right one for the right job. This is just me, but I would never use King Tut or silk for piecing. King Tut is a marvelous thread to quilt with though and silk is more for quilting or applique because it is so fine it sinks right down into the fabric and is nearly invisible. I use finer threads in quilting when I don't want the thread to be obvious or I am worried about build up. Alternatively if I want the quilting to really stand out I will use a heavier thread. It is great that you want to experiment; this way you will know what threads you like best for which tasks but don't ever limit yourself to just one thread for everything because you are doing yourself a disservice.
Thread can be almost as much fun as fabric!