"Do we ever twist the spine. I asked on Wednesday. This couple are among the top 30's in the world they are also currently having lessons with John Wood Michael Barr Andrew Sinkinson who will be here in a few days time, and the list goes on. I asked do we twist the spine at any time , the answer we never twist the spine."
The problem is that you are asking it as a loaded question to which many might on instinct disagree. Quit asking silly questions and spend time actually studying their dancing, and you will learn that it is indeed necessary for the hips and shoulders to rotate at different times in many situations, and even to sustain different alignements in situations like promenade.
"Somebody mentioned the Throwawy Oversway. This is the only time the man arches the spine, this is not a twist."
It is both a long arch, and also a situation where the hips and shoulders do not match. Describe that however your wish, but the reality is that it happens.
"At last I think I have figured out Anonymous's mistake. He is putting a verticle lowering as in the Waltz and trying to put it into a linear dance which is the Foxtrot. That would explain why he believes the thigh is verticle over the knee."
No, you have it exactly opposite. Neither the lowering in foxtrot nor the lowering in waltz is vertical - both progress. This confuses many people, because during the lowering in waltz the feet do not progress the way they do when we take a step while lowering in the foxtrot. Yet the body must still progress. Those who don't understand this try to keep the body weight in stationary as they lower in waltz, by sending the knee forward alone. The proper way however is to bend the knee forward, and move the body forward with the knee. This means that the body is progressing during the waltz lowering, and incidentally it means that the body will be vertically over the knee, RATHER than vertically over the standing foot.
"I can perform CBM and CBMP without getting my spine out of alignment."
Of course, you must keep alignment of the spine. But you rotate your body around it, and in many situations not everything will be facing the same direction.
"If you were to twist your spine on the first step of Reverse Turn. What a mistake."
Dancing a good reverse turn requires that you delay the rotation of the shoulders until very late in the first step - if you bring them through too soon you will shove your partner across you to the wrong side of your body. So your choices are either not to use any CBM in the reverse turn and wait to turn until step two (which is not CBM). Many leading teacher say that this is what they way. But I don't think it really is. Instead, what they want is probably the same as those who teach that reverse CBM begins in the knees and hips which rotate early in step one, and gets to the top only at the end of step one. Differential rotation - lower body first, upper body afterwards.