A Friend I Once Had, And The Dogmatic Principle

I just wrote an e-mail to a friend, and the last line caused me to stop and cry for several minutes. What was the word, the thing freighted with so much meaning to cause me so much pain? "Family." We throw around the phrase "church family" in such a buzzwordy fashion that it doesn't mean what the words mean. God help me, I may love my church family more than my own blood. My pastors, my elders, and everyone else are somewhere between brothers and sisters, and fathers and mothers. I joined another church nearer where I live as an associate member, and I love them too, but it's nowhere close. No disrespect. Nearly every post here for about a year has been about the open and frank investigation of Roman Catholicism*, even if not stated. Provoked in me by an (apparent) inability of Sola Scriptura to provide definitive doctrinal guidance, to settle disputes, to silence heretics. And as a person who desires/desired to minister in the Reformed tradition, I was troubled by the fact that a "plain" reading of Scripture (whatever that means) did not vindicate that position. Within that camp, I quickly became aware that while many holy and godly people were discovering valuable things in all sorts of areas, whether we admit them as "biblical" and within our bounds of orthodoxy is largely a question of hermeneutics, and some of this is impossible to test or assign a moral value. Again, it may be an inherent weakness in Sola Scriptura as a principle, since all appeals to scripture are appeals to an interpretation of scripture. Granted, the proper disposition/submission to the Bible as God's revelation, and a desire for its intended meaning applied in one's life helps most people avoid the most monstrous (Christological) heresies most of the time. But it doesn't help earnest doctrinal disputes, nor does it help resolve the visible disunity so apparent to us. We can pretend at an invisible unity in some appeal to the "essentials" (without agreeing what those are) and can downplay those historic differences as Protestants if we want, but if they were insignificant, we wouldn't be divided. The ecumenical creeds cannot accomplish this for us, since we mean different things by them, and we each differ from their original meanings in context. I thought perhaps Keith Mathison's excellent book, The Shape of Sola Scriptura would help much of this, but it did not. Drawing a distinction between Sola Scriptura and Solo Scriptura, Mathison wants us to tether our historic confessions, biblicism, and traditions to the "rule of faith" in the "Church." This will keep us from a radical individualism and error. But how do you define "the Church?" What are its marks? And if we all differ in governance, sacraments (number and meaning) and doctrine, it cannot be one, despite the Lord's mind-boggling grace to allow such commonality to exist despite us. Mathison inadvertently concedes the existence of many churches when reminding us to flee a church that fails to celebrate the sacraments, as if the common signs and (some) common practices meant we were observing the same rites.
I must say that what I think is the 8th chapter (the problems with "me and my Bible" or Solo Scriptura) almost made me a Catholic by itself. I wonder if anyone else felt the same. I personally fail to see a real difference in the two concepts. Furthermore, tradition would be more useful if an appeal to it were not 1) ad hoc; and 2) individualistic.
Our esteemed author also misunderstands Catholic doctrine in a few cases, but it could be worse. I loved every page of this book, despite the problems.
I am not yet a Catholic, despite all that. The Catholic Church must be proven to be: the Christian Church in all ages, and necessarily infalliable. If not, its distinctives are at points bizarre enough to offend the conscience, and its claims' implications are too painful and costly to be entered into lightly.

Note: *The 'I Am On Fire for God So Completely That Loyola Seems Like an Unethical Vaccuum Salesman' kind of Catholicism, not the 'Choose Your Own Adventure' kind.