Maybe I can help you grasp my distinctions a bit better.
Sola Scriptura is the claim that the bible is the only FINAL authority - it is the claim that we are REQUIRED to always "check it out with Scripture" (for example a voice). This contradicts the (tautological) rule of conscience expressed probably a 100 times on this thread, and also contradicts the facts of Scripture - the bible EXAMPLES of where the divine Voice availed of the rule of conscience time and again, in fact it contradicts even the Inward Witness itself. I did not have "check it out with Scripture" to become a Christian, rather the Inward Witness convicted my conscience DIRECTLY, and thus availed of the (tautological) rule of conscience.
I've tried my best to catch up with this thread and not jump in misinformed on the direction it ha s gone, but I'm still perplexed about some of the claims made about sola scriptura here.
This post in particular I thought was interesting because I would want to know why / how the inward witness convicted your conscience. In other words, did this happen when someone was preaching? Or a friend was talking to you about Jesus? Or did the Inward Witness arrive one day while you were sitting on the couch eating a sandwich, and there was no correlation between it and anything you ever heard before?
The whole point of scripture is that is provides us with the revelation of the gospel in Jesus Christ, and it is the gospel that is the power of salvation. (Romans 1:16.) Arguably, even the phrase "Word of God" refers not to much to the Bible (although by implication it can) but to the gospel message of Jesus, the living Word. That is why the "Word of God" is also the "Sword of the Spirit".
Sola scriptura, if you go back in its history, was the claim that the Scriptures provide the clearest and oldest and most reliable revelation of the gospel, and since the gospel of Jesus is the clearest representation of the face of God (the "face of God found in Christ") then it is the gospel that ought to be our guiding "hermeneutic" in all of theology and revelation and Christian living. The Old Testament (as Paul and the apostles show) points to this gospel, and the NT explains it. Therefore, the Bible has final authority not because God is interested in words on a page but because it contains the gospel.
Furthermore, Reformers stated that the gospel must be preached and proclaimed- the Word must be communicated as word. This throws out the idea that exegesis and study was ever the main point of revelation, even as helpful as it may be. The gospel has inherent power of its own to strike the conscience and bring it peace and it must be proclaimed.
Conscience has to be bound to something, it does not exist freely on its own. God binds it to Law naturally but over time we change Law to suit our flesh so that we can try and bring our conscience in line to our flesh. However, when we bind our conscience to the gospel then we experience peace because it tells us that Jesus died for us, defeated evil, and we are saved by grace etc. An Inward Witness is a witness to something, which is the gospel, which is an external witness. We are changed from the outside in, and only then from the inside out.