2Co 10:13-16 (NKJV)
We, however, will not boast beyond measure, but within the "limits of the sphere" (KJV "rule") which God appointed us—a sphere which especially includes you. For we are not overextending ourselves (as though our authority did not extend to you), for it was to you that we came with the gospel of Christ; not boasting of things beyond measure, that is, in other men’s labors, but having hope, that as your faith is increased, we shall be greatly enlarged by you in our sphere, to preach the gospel in the regions beyond you, and not to boast in another man’s sphere of accomplishment.
Only the KJV uses the word "rule" so you are basing your argument of an archaic form of English (Late Middle English) which is no longer spoken.
In that Late Middle English, the referenced passage is talking about the geographic areas where Paul preached and the foundational work of other evangelists and apostles, not the "canon of scripture."
Gal 6:15-16 (KJV)
For in Christ Jesus neither circumcision availeth any thing, nor uncircumcision, but a new creature. And as many as walk according to this rule, peace be on them, and mercy, and upon the Israel of God.
Retaining the context of verse 16, it becomes apparent that Paul is talking about the principle that circumcision had been rendered irrelevant by the Gospel. It is not used as the word "canon" would be applied to a set of of books.
With reference to Phil 3:16, once again, it needs to be read in context.
Phl 3:12-16
Not as though I had already attained, either were already perfect: but I follow after, if that I may apprehend that for which also I am apprehended of Christ Jesus. Brethren, I count not myself to have apprehended: but this one thing I do, forgetting those things which are behind, and reaching forth unto those things which are before, I press toward the mark for the prize of the high calling of God in Christ Jesus.
Let us therefore, as many as be perfect, be thus minded: and if in any thing ye be otherwise minded, God shall reveal even this unto you. Nevertheless, whereto we have already attained, let us walk by the same rule, let us mind the same thing.
Again, this use of the word "rule", taken in context, is not used with reference to a set of books. It is with reference to a principle of behavior..
A word's meaning is not separate from the context in which it is used.
Using the Late Middle English of the KJV is prone to error because of misunderstanding the meaning of the word as it was used 500 years ago.
To me, it appears that Paul's use of the word "rule" has nothing to do with fixing a specific set of books as the "rule" by which all other writings are measured.
Maybe I missed the point?