Forgot to add: I know that the Council Fathers never use the word "transubstantiation," so precisely what they mean by "the body and blood of Christ" is open to interpretation.
No, SC does not explicitly say that the Mass "is the propitiatory sacrfice to God of a spotless victim" nor does it use the term "transubstantiation" because it did not need to. The document is premised on these beliefs. That is, the Council Fathers did not think that they had to restate everything that was said by earlier popes and councils, including Trent. This was true especially of article 7, which listed the presences of Christ in the liturgy, and article 41, which concerned the nature of the Mass. The Council Fathers amended article 7 so that it would specifically reference the presence of Christ in the Eucharist because the draft of the document did not include this reference. Like the other documents of Vatican II, this document must always be read in the light of Tradition, that is, in the light of what the Church has always taught. These documents should NEVER be interpreted as repudiating the teachings of earlier popes and councils. BTW, Pope Benedict has said the same thing, that the Council must be interpreted in the light of Tradition. Catholics should listen to the pope and not to some schismatic bishop.