No, I don't think we need "rely" on them. We can surely take their advice but to "rely" on them is foundation for error as we have seen many fall for. We know that Paul had to correct error in his day. We know that most of the "churches" by AD90 had allowed error to creep in and where warned by Christ.
>>My argument is that those canons themselves were derived from what the local churches had received as Scripture and were using.<<
Risky at best. As we see in Revelation, the "chances" of you being on the right track is only one in seven. That's only a 14% chance of being correct. There is no assurance that those second century "churches" or even the "church" leadership were correct as we know error and false teaching was already present in the first century. To invoke second century or later and "rely" on it without comparison to what the apostles taught is worthless for those seeking truth.
>>Here's the key: It was not theory. It was practice.<<
As we have seen in the message to the seven churches in Revelation, "practice" in even the churches of the later part of the first century was no assurance of correctness.
You argue for the inclusion of books that have proven errors. You want "inerrant" yet care not whether whether or not those books have errors within them. You invoke first century churches yet ignore that 86% of the churches even in the last part of the first century were rife with error. I for one am not impressed with your "arguments".
Paul commended the Bereans for "searching the scriptures daily" and said anyone who taught what they did not to be considered accursed. On those two counts alone the Catholic "arguement" is left wanting.
The Bible you have came to you via a long, long, long chain of human provenance.
Where to start, where to start...
Tell me: is the OT in your Bible based on the Masoretic Text? Or some other. Please explain.