Your logic is incredibly wrong.
Hord>Sith is correct
Revan=Sith is also correct
Hord greatest of the Sith years before Revan, so would he better then Revan when Revan was around?
My guess yes, does he have to be in all forms? No, but he probably is doesn't matter anyways with the things he has going for him he would own Dooku.
You're missing the full quote. He's the best lightsaber duelist of the Sith up until Revan's time (given that it was when the quote was issued). Does that mean it's impossible someone has eclipsed him since then? No, but it's unlikely.
Does that mean he is greater than all previous Sith that used swords? Uncertain, but again, impossible to tell.
From the one quote we have of him, we know he MUST have been very good, and I would argue definitely good enough to waste Dooku, but to say anything along the lines as Tulak being best ever because of one person saying one quote is being daft.