Dieselman, I'm sorry if I didn't make my point clear (I have that problem often). Let me try again:
You say the ethiopian needed help to understand the Bible. If someone tries to understand it without having someone else explain it to him, then he thinks he's better than the ethiopian (your words). So does the GB receive some help from someone else, or do they interpret the Bible alone? Version 1: they interpret the Bible alone = they are better than the ethiopian.
Version 2: they get help from someone. Who is that they are getting help? Is there some other group of men who teaches them? That would just lead to a circular logic (as in who teaches those people? etc.) I assumed your answer would be they get help from the Holy Spirit. Good, that's a good answer - true Christians should get help from the HS. Now, you said the HS is not the propriety of the GB - that's great news (I think the GB disagrees with you, but I don't want to open that can right now).
So if I read the Bible alone, if my motives are pure the HS will help me, and I arrive at the correct understanding of the Bible, without ever reading any so-called Bible-based literature, or having someone (else than the HS) explain it to me.
This is 'sola scriptura' - scriptures alone. Is the WTS promoting this course of action, as outlined above?