Well, i am not a specialist in history, however i think the agoge wasonly to spartan citizens.
The "Perioikoi Hoplites " were not Spartan citizens, so tech shouldn't affect all Hoplites, only Spartiates.
Decreases the cost of tech as it no longer affects hoplite citizens.
EDIT: Spartan champion are supposed to be the strongest infantry in the game (spearman). Macedonian Champion Silver Shields are equivalent and without the training time penalty acquired with "agoge" tetch.
My proposal:
Decrease health to 20% and give an attack bonus 15% (makes sense, it was training) and keep +10% training time. The cost decreases to 300 food 300 metal.
Silver shields it's purely armor, so it makes sense to gain only health and armor. Agoge gain less health but also attack too. See also D2856.