For each farm governor you also need a good general to march your big armies. Large forces are only good if you have good generals to march them with.
It is always best to march according to your general’s strengths, as this will give you the best use of his/her bonuses. For instance if you had a general with infantry defense, arc attack, troop speed, and manuevering (probably the most ideal I can think of off hand) you would want to march him with infantry and archers only. Probably 3 : 1 :: archers : infantry. Having any cats or cav in the mix would decrease the amount of total bonus your troops would have.
So if u had a general with infantry atk and defense u would want to march infantry only with that general. This can be a bit tricky as in that latter case if u only sent that inf general without the support of archers you could potentially lose alot of inf as they attack last in a battle.
Arriving at the next point of discussion. It is best to have a varying spread of different types of, what I would call, focused generals. Most large battles u will take part in will be on single targets. All timed to arrive at a single point at once. This means that you will have the support of all your various types of units and the various types of units your mates possess. E.g. Currently I have 3 focused generals one inf only, one arc only and one cav only; and 2 mixed .
Last, but not least for a cat army you obviously need a speed bonus and -fortification (wall damage) if he/she has cat atk or def this is a plus)
Again you always want to play to your general’s strengths. Always