First of all, there's no need to switch between sharps and blunts on one dungeon level in The Hell. On all levels you will face either Undead or Demons+Animals. As before, blunts do 2x damage to Undead and 0,5x damage to animals. That's why using a mace of dmg 4-20 vs undead is better than using a sword of dmg 14-78 against them. Here is why: [4-20]x2=[8-40] (blunts vs undead), and [14-78]x0,5=[7-39] (sharps vs undead). Get it?
Sharps do 0,5x damage to undead and 1,5x damage to animals
Bows, crossbows, axes and staves do NOT have such damage modifier.
By the way, there are weapons that yield +100% dmg vs demons, but these will be magical or unique. All melee weapons can have such bonus on them.
Assassins and Gladiators using sharp in one hand and blunt in another will do blunt type damage.
Now regarding defense.
I recommend getting '-50% all ranged damage' items a.s.a.p. and also getting as much '-damage from enemies' items as possible. Believe me, these items are a 100% must.
You can reduce melee damage from monsters even further if you use Arcane Shield spell.
Magic/Fire/Lightning resistances will decrease your elemental damage even further if got from corresponding source.
Finally, study this Guide, if you haven't done so yet. Read it at least 3 times over. I'm serious. Do it.
As usual, if there's something you want to know (ask) about on this topic, just ask here 
