Ah right. Yes.
You don't need academies or tracks, but if you must, it's better to surround the academy or track with demons or centaurs than a demon or centaur with academies and tracks.
Use Golems around the Blacksmiths. Throw in a Demon or two.
Use Demons around the Altars. You might want to throw in a few Golems there.
The rest of the map should be filled with Centaurs in every square that can be spared and flying monsters (Manticore or Vampire) where the Centaurs can't reach.