I don't think IronFlesh or heavy armour on cav saves your ass cuz of the speed bonus most of the hits you take no matter if its ranged or melee will kill you,your horse or both of you most of the times therefore i always try to max my damage on horse and i use champ arabian war horse + lance + mighty GLA on my back.That build worked fine for me when i was a cav.I found playing light cav and hunting ranged from behind,flanking infantry etc more fun then riding your horse like you ride a panzerkampfwagen Tiger IV.
My fav. cav build :Level 30 (4 420 577 xp)
Strength: 21
Agility: 18
Hit points: 56
Skills to attributes: 8
Ironflesh: 0
Power Strike: 7
Shield: 0
Athletics: 5
Riding: 5
Horse Archery: 0
Power Draw: 0
Power Throw: 0
Weapon Master: 6
One Handed: 1
Two Handed: 1
Polearm: 156
Archery: 1
Crossbow: 1
Throwing: 1