I don't think that it should come as a surprise that TEs might be considerably less certain about the specifics of their theology of creation than are YECs. It seems to me that, for the most part, one principal distinction between the two groups is not so much their specific views about the origins of the universe, but rather their broader views about biblical interpretation and certainty in general.
The YEC perspective seems to come in large part from an understanding of God and an understanding of Scripture that insists upon a high level of certainty in our understanding of God and Scripture. From experience most YECs see the Bible as a sort of magical answer book that we need only consult to find the solutions to the daily questions of this life spelled out in plain and simple terms if only we are ready to accept and believe. Thus, the Bible is not seen as a product of a time and place (or various times and places) in human history, but rather as a text that completely transcends time and place and speaks directly and plainly to all people who read it with an open and willing heart. Therefore, while it may be benefitcial, it is not necessary to understand the historical & social contexts of the times and places in which the Bible was written. Furthermore, it seems to me that thet YEC position demands certainty of action from God. Therefore, it is expected that God acts as a mirco-manager of the universe, and leaves nothing to chance. Thus, everything that happens in the world, good and bad, is either the will of God or the work of Satan.
The TE position (or at least the position that I myself accept) stems from a much different view of God, Scripture, and certainty. It seems to me that most (Christian) TEs see thet Bible less as a magical answer book and more along the lines of a well-written textbook. A good textbook does not simply tell the reader what he or she is supposed to learn. Instead, it provides information and guidance necessary to stimulate the thinking that will help the reader to discover for him or herself what needs to be learned. It contains far more questions than answers, and the information that it does provide is only the stimulus for a deeper journey of discovery. This view of the Bible sees it as clearly being the product of the times and places in which it was written. Thus, it is essential to consider the historical and social context of these times and places. Furthermore, the TE position seems to be far more accepting of God of free choice and random chance. This view sees God as remaining comfortable with His Soveriegnty, even though He does not directly control everything that happens in His universe. In this view, many of the the good and bad things that happen to us in ouor daily lives might be the product of the hand of God or of Satan, but it is far more likely that they are just products of some combination of random chance and free will.
I am absolutely sure that the above analysis oversimplifies the matter significantly. But, I think it does help to explain why the Creation/Theistic Evolution discussion is so difficult, but also why it is so important and compelling. And, it should explain the results of the survey and the apparent wishy-washyness of TEs (I am actually surprised that several people said that they are 100% sure of their interpretation of Genesis; This fact in itself demonstrates perhaps that I have oversimplified a bit).