Dang... im used to the Seleukid Gov 4... which gives a +5% law bonus, or happiness... dont recall... but its mighty usefull when blitzing over the steppes...

But, its been a while since ive played Baktria, and should not participate in this topic, but as far as army composition, i recommend using Phalanxes in favour of... Hippotoxotai and Prodromoi instead of Cataphracts...

And the best Garrison unit is by far in case of unkeep-troopsize is Pantodapoi or Persian Archer Spearmen