F.F Bruce, The Canon of Scripture, p234.
If you're going to appeal to the various Councils for the canon you're about to wipe out a great deal of Roman Catholic mariology.
IF you accept these Councils that is.
Not so fast. Although the manuscript tradition is uncertain, the generally accepted reading is that he listed the 14 letters of Paul, thus including Hebrews. In any case, there is still the 1000 year history before Trent of the general acceptance of the canon listed by Pope Damasus and the North African councils, including Hebrews. At best you can say that there was no solemn proclamation of this until the Council of Trent. But even here you would be wrong because there was one at the Council of Florence. And if we are to be limited to formal definitions, do we then say that Christians did not definitively hold that Jesus is the uncreated Son of God before the Council of Nicea?
Furthermore, if you are to say that the Catholic Church did not define the canon until the Council of Trent, then you must also hold that there was no firm canon of the Bible for any Christians before the 16th century. Thus my original point stands, that for the early Christians "sola Scriptura" could not work because there was no way to be certain what was Scripture in the first place.