Ya, I could not find it. I did find the thread where I thought I posted this thing, and my post said that I'd worked up a big long post, but it was off topic, so I decided not to post it.
So... since you asked so nicely, I'll give you some numbers to think about.
Part of the problem of asking "against dexxies" is that there's a lot more to consider than against monsters, that will just hit you (hard). Dexxers have a host of special moves to choose from.
Lets simplify things. We will make a few assumptions. First (most important) both you and your attacker have 120 WS. In PVP, I assume this is a given; PVM - maybe not, some monsters have >120. Also, we need to decide whether or not you'll be mounted. In PVM, we'd assume yes, in PVP, I'd say this is not a safe assumption. Also, in PVP, I think we can safely assume that your opponent will have 45 HCI. In PVM this would be 0.
Here's the hit chance formula from UOSS:
Hit Chance% = ( ( [Attacker's Combat Ability + 20] * [100% + Attacker's
Hit Chance Increase] ) divided by
( [Defender's Combat Ability + 20] * [100% + Defender's
Defense Chance Increase] * 2 ) ) * 100
So, we're looking at: ((140 * 145) / (140 * ((100+DCI)*2))) * 100 as the chance that you'll get hit.
Lets take a look at some possible values of DCI:
With -5 DCI (lets assume you refined for 75 resist, takes you down to 20 base, and then you get hit by HLD): 76.3%
With 0 DCI, the chance you'll get hit is: ~72.5%
With 20 DCI (what you're left with when you have 45, and get hit my HLD): 60.4%
With 45 DCI: 50
With 70 DCI: 42.6
Note that this all assumes you've got no chance to parry, and no chance to reduce your opponents HCI (I suppose ideally you'd run HLA, but that might not be a possibility on your looted splinter butcher knife for instance).
So, lets look at the expected damage per swing. This is Damage * chance to hit * armor reduction. Lets pick a nice round number for the weapon damage: 50 (actually this is pretty reasonable too, like someone using a butcher knife or something is probably right around 50 damage). Note I will assume you're all 70s even past whatever the opponent may do, or your own spells (corpse skins etc).
@45 dci: 50 * .5 * .3 = 7.5
@20 dci(45 + penalty from HLD) = 9
@70 DCI (now you only have 65 armor) 50 * .43 * .35 = 7.6
@45 DCI (65 resist, but you've been HLD) = 8.75
Hmm, so in PVP, it lo0ks like it doesn't really matter, you're either getting hit for 8 or 9 damage per hit no matter what. BUT... now you need to account for all the OTHER stuff that comes with "getting hit" means.
Most people in PVP are going to use some sort of special, or rely on their weapons do do something other than "deal weapon damage". In almost all cases you want to get hit less, but right more damage per hit, IMO. This will prevent you from getting poisoned/bleed/splintered/para'd/AI'd/mortal/ etc, none of which really takes your resists into effect.
One interesting thing to ponder would be hit spell. Lightning, per UOSS, does 30-34 base damage. If you've got 70 ER, then 34 * .7 = 10.2, 65 ER = 11.9 damage. Lets try to include this in the above calculation.
Lets assume a weapon with 50% Hit Lightning.
Now the calculation is (weapon damage + (spell damage * hit spell chance)) * resist) * hit chance
@45dci: (50 + (34 * .5 )) * .3 * .5 = 10.05
@20 dci: 12.06
@70 DCI: 10.08
@ 45 DCI: 11.73
Looks again like the 70DCI comes out ahead on an expected value per swing standpoint. Granted, we know you're not taking 10 or 12 damage every 1.25, you're taking either 0, 8 or 18, or 0, 8, or 21.
Given that so much of the value of a weapon in PVP comes not from the weapon's base damage, but what ELSE it can do when it does hit (specials, hit effects, etc) and that the kind-of worse case scenario is that when you do get hit, you only take 3 more dmg, it seems to me that in PVP, 70 DCI is the way to go against a dexxer.
