Cheers Dundee,
I'm not sure why but my armour of faiths have always stacked. I'm using all the latest official patches for ToB and haven't got any 3rd party additions that could cause such an error. I cast hardiness first because if you cast the faith armour first and then cast hardiness then all melee resistances are set to 40%. So I can get 40% from harndiness and 25% from each of 3 armour of faiths. This gives me 115% resistance to slashing crushing piercing and missile which is a bit daft because you are healed when someone whacks you with a large sword
My latest if rather expensive tactic is to keep 2 rods of resurection in my quick item slots. Each rod gives 10 charges, and when you use it on your character you are fully healed. Its mega useful in the heat of battle, especially when iron golems can dish out over 100 dmg on insane. With a rep of 20 and a charisma of 19 (the charisma that gives you max discount on goods - values beyond this have no effect on item cost) a rod of resurection costs around 4400 IIRC, which works out at 440 gold pieces per heal which is a bargain to say my beastmaster has 250+ HP, and a heal costs 750 in a temple anyway. Once the rods are down to one charge each, sell and buy back. Very useful.