So for 100% PvP horse - should I level all speed on the Light horse for 74% speed? I know stamina can avoid knockoff but if they can't catch you, you don't have to worry as much and I assuming they will fix the unlimited stamina bug.
Well, the catch there is ambushes. Extra speed won't help if you're running into the enemy as opposed to away from them. As long as that's not an issue for you though, it will be a big help getting around Cyrodiil.
"He who fights with monsters should look to it that he himself does not become a monster...when you gaze long into the abyss the abyss also gazes into you..."