Was Paul a member of the Sanhedrin Council?

I believe it is quite likely that Paul was a member of the Sanhedrin council. I think this for the following reasons:

• Paul cast his vote against the Christians, showing that he belonged to some sort of decision making group. Acts 26:10-11:

I not only locked up many of the saints in prison after receiving authority from the chief priests, but when they were put to death I cast my vote against them.

• Stephen was seized and brought before the council. Paul was implicated with Stephen’s death sentence, possibly indicating he was part of the council. Acts 22:20:
  

  And when the blood of Your witness Stephen was poured out, I myself also was standing by and consenting to his execution, and holding the garments of those killing him.

• Paul was brought up at the feet of Gamaliel, who was a member of the council. It would not be surprising if Gamaliel’s star pupil followed in the footsteps of his master. Does Galatians 1:13-14 give a hint that Paul was a member of the Sanhedrin council?
  

  For you have heard of my former life in Judaism, how I persecuted the church of God violently and tried to destroy it. And I was advancing in Judaism beyond many of my own age among my people, so extremely zealous was I for the traditions of my fathers.

Summary of why I think it likely that Paul was at one time, a member of the Sanhedrin Council:

1. Paul “cast his vote against” the saints.
2. Paul consented to the execution of Stephen, a decision made by the Sanhedrin.
3. Paul advanced in Judaism beyond many of his own age.