Tabard of valor, improved mettle, and UMD

[Hirax]

"Whenever your current hit point total is equal to or less than one-half of your full normal hit points, you gain the mettle ability: If you are affected by a spell that would normally have a reduced effect on a successful Fortitude or Will saving throw, it instead has no effect at all upon you if you save successfully. If you already have mettle from a class feature or some other source, you instead gain improved mettle, which halves the harmful effects of a spell on a failed Fortitude or Will save while still protecting you entirely on a successful save."

1. What would be the applicable UMD check to have a tabard active with full hit points? Activate blindly for DC 25, with +2 on subsequent checks?

2. I've just now looked at the text in addition to the table (what a concept!), and realized I've been using UMD wrong. I'm trying to mimic a first level pious templar, meaning the DC is 20+1=21 to gain improved mettle? I had previously thought it was a flat DC of 20 to pretend you have any class feature. The DC for wands and staffs is only 20, because you're trying to mimic being level 0 in a class to have something on your spell list, right?

3. Most importantly, how the heck does improved mettle work? Halving the effects of something with a binary result isn't explained at all. Looking at improved evasion as a reference point, on a failed save, a character with improved evasion suffers the effects of what would happen if a normal person made their save, against things such as fireballs, breath weapons, etc. Applying improved mettle in the same fashion seems too powerful, because that would make you immune to anything that was will or fort partial.

[Hirax]

Knock knock?

[Curmudgeon]

None of the above.

There is no option in Use Magic Device to emulate a specific hit point total. While you could emulate the level 1 ability of a Pious Templar, that's only good for activating a device. Unfortunately, emulating already having mettle isn't going to help you activate a Tabard of Valor to gain mettle; for that you need to have a specific hit point total.

[Hirax]

I thought that was half the purpose of the activate blindly section? Skip Williams wrote (http://www.wizards.com/default.asp?x=dnd/rg/20041116a) that "you can use the "activate blindly" option with any kind of item," so I've always taken the approach that it's just a matter of picking the most applicable of the options UMD gives, then activating blindly if none fit. For that reason, the activate blindly text seems to go fine with a tabard of valor to me: "Some magic items are activated by special words, thoughts, or deeds. You can activate such an item as if you were using the activation word, thought, or deed, even when you’re not and even if you don’t know exactly what to do. You do have to perform some equivalent activity to make the check (Rules Compendium version)." I'm aware Skip Williams' writings are wont to contradict RAW, but they do provide clear insight into RAI, and in this case I don't believe what he writes contradicts RAW. Unless of course it's an item such as a runestaff or domain staff; you can start an engine without a key, but that won't matter if the engine needs gas.

But regardless, I'd be content to walk around with half hit points in some cases, depending on how that heck improved mettle works, which I'm still hazy on. edit: also, I wasn't trying imitate having mettle to help get mettle, I was doing it to get improved mettle.

[herrhauptmann]

My guess for Improved mettle:
If a spell says Fort/Will saves for half/partial, and you fail, you still only take the partial effect.
So even if you fail your save vs disintegrate, you don't get turned into a pile of ash (unless that 5d6 damage is enough to kill you)

So pretty much like evasion/improved evasion.
Evasion: Successful save, no effect. Failed save, full effect.
Improved Evasion: Successful save, no effect. Failed save, still only half.