Yes I agree completely. The only trees I think are useful at this point are the hemlocks and the eastern white pine. The hemlocks average out to 40.9%. I know there is more white pine data, I just don't have it organized and would need to compile it. There are many large eastern hemlocks and white pines in the old growth section of Cook Forest. I am very familiar with these trees and can say that breast height is typically above the basal flare.
The one consideration here is that if the top of the tree has been broken very much below where the original tapered top would have been, then the percentage of cylinder occupation will be increased. The largest percentage in the hemlock listing - the Jim Branch Giant - has such a broken top. Some trees have the swelled base extending farther up the trunk, others have a top broken out and are shorter than an idealized form. This is how any set of trees will look. I am unsure how the overall shape changes as the tree matures.
As I said before, this is the data we have. The hemlocks to me seem to be the best representative of what might be expect from your spruce in terms of shape and volume. The best girth for the calculation should be taken above the swelled base - thus the 4.8 meter option. I could do better estimates and get a better idea of the ranges of volumes as the tree shapes varied in a mature conifer if we had more measurements. This is, as far as I can see, the best option for addressing your original question, and my feeling it is as good of an estimate as is possible at this time.
"I love science and it pains me to think that so many are terrified of the subject or feel that choosing science means you cannot also choose compassion, or the arts, or be awe by nature. Science is not meant to cure us of mystery, but to reinvent and revigorate it." by Robert M. Sapolsky