I built a frame or two using the eyeball the ht/st alignment method. Of course, you also have to check that the DT is parallel to the sides of the BB shell or you have real problems. There was a post from someone on the framebuilders email list that said he used that method for his first 100 frames. It's really slow, and you have to be meticulous, and you still might end up with a crooked frame, so it's not for everyone. OTOH, you can easily end up with a crooked frame if you rely on your fixture too much, so there's that to consider as well.

Unfortunately, I can't use this method anymore, eyes are bad.