Ok, before anyone else tries to argue on what I said, I will make myself completely clear. To do so I'm going to use a very simple analogy that should make everyone happy.
To start out, lets look at it this way.
FACT - Revan had a holocron full of Sith rituals and Dark Side philosophy. Let's call this fact, number four or "4".
FACT - Revan visited Malachor V and discovered the Dark Side Academy on the world.
FACT - Revan visited Korriban after rediscovering its location on Malachor V.
The latter two fact's we should call number one or "1".
Now, we have: (1 + X = 4).
RATIONAL ASSUMPTION - Revan learned Dark Side lore from Malachor V.
RATIONAL ASSUMPTION - Revan learned Dark Side lore from Korriban.
Let's call those two number three or "3".
Now, we have: (1 + 3 = 4).
It follows a rational process, which is all I am trying to say. I am not specifying exactly what Revan knew, nor am I trying to say that he knew more than any specific character in the mythos. This is my stance, it is clear and precise and I will say nothing more.
And if any of you bring a certain Scottish empiricist into this debate I'll yell at you.