The chance of absorbing damage for an equipment type is the chance you will be hit in that area (all the values add up to 100). Presumably if your character does not have a shield the values will be weighted to reflect that (the 30% (or whatever) chance to absorb damage gets distributed to the other armour types). I played using one and two handed swords, and besides one handed weapons doing less damage, biggest difference the shield made was in the extra equipment bonuses or charm slots (didn't notice a big difference in the damage I took).
The armour class of a helmet is only used in the 10% of the hits that targetted the head. The stats window lists an overal armour class, but that is for informational purposes only.
Realistically, you would think any damage not blocked by a shield could be partially blocked by whatever armour was behind the blow, but I do not know how intricate the combat calculations are in the game.
With only a 5% chance of being hit in the feet, I think the bonuses are more relevent than the armour class for shoes and boots. I used a pair of AC 70 boots for the last half of the game: Charm Quality 5 (though I didn't add any charms), 2 Defense, 80 Vitality, 80 Magic, Identify +1.
I would take a primary stat bonus (especiallt strength, early in the game) over resistances, so concur with your choice of boot.
The first orc warlord I ran into south of Aleroth I had to keep withdrawing (kill off all the regular orcs first and then take him on alone). The orc drummer could not hurt me, but I could not do enough damage fast enough to kill him. After buying a better sword from the traveling merchant near the cursed abbey, I had much less trouble with the orcs.
I did the same as you, boosting strength to equip weapons, then having to make up for a low agility later. I had a little help, though, as the dragon rider that Zandalor kills south of Aleroth dropped a gold strength charm. After meeting the knight near Stormfist castle and getting a pretty good two handed sword, I had to go up another level or 2 and add the strength charm to an amulet to be able to equip it (that was the only charm I used in the game, though I collected lots).
To determine how much agility was required to reach the limits of the hit percentages I loaded an old save with my character at level 3, used
iZakaroN's SaveEditor (or from
Kiya's site, with description) to give myself 100 stat points, loaded the game, and added points to agility, checking the offense/defense descriptions for the hit percentages.
If you can not be killed in a couple of hits by a strong opponent, then your constitution is high enough (though if that is all you can handle you may go through a lot of healing/restoration potions in tougher fights).
