Pointed at D2846.
"special_war_horses" gives the player a +20% health for all cavalry (including champions). Cost is not equivalent to its gain.
"mace_silvershields" must have research time equivalent to similar tech.
My proposal:
Increase the research time to 60 for upgrade_mace_silvershields;
Increase the cost of special_war_horses to 400 food / 400 metal (double current value).
It could cost more (special_war_horses) for the benefitPointed by @Nescio, Nisean horses were used for heavy cavalry, but I think cavalry techs should cost less than infantry becauso it only makes sense they cannot get resources like infantry,o affect champion cavalry. so investing in cavalry is always a bigger risk.
Cost 350f 350m (value equivalent to other techs).