Catapults and walls


Have seen some posts regarding the use of CAT's being isolated as only being used against Walls.

I would first make the correction, that with the research of 'Stone Hail' Catapults can also damage the buildings inside the city. Hit a Farm and you make a big dent in the defenses.

My question though is how to deliver a CAT offensive to a wall and protect them? My mistake was sending them out with HS and SL attack units. The CATS were decimated, possibly due to flyers.
Their defense is about the same against all, but imo I will not send CATS out without ARCHERS OR CH. Possibly HOPS or Divine Envoys.

SL and HS may be great for attacking but are lousy defenders. Something needs to protect the CATS while they do their thing. Please give me your critique or thoughts on this.