Yoma 59: Is There Revelation through Blood?

Sprinkling on the "pure" of the altar - the Gemara puzzles out what this pure is. Possibly, the midpoint of the altar wall. Possibly, an indication of revelation, as the prooftext of a verse in Exodus suggests. Also, what happens when a Tanna changes his mind to agree with a different Tanna...?! Plus, what happens to the blood that runs off, into the Kidron River, no less? And if one uses that blood - as gardeners were said to do - how much so they have to worry about me'ilah (misusing that which was consecrated)?