Many fade-touched materials relate to a skill or ability used by one of the three classes. One that immediately comes to mind is "on hit, gain three guard." Guard is typically for warriors only. If you use a fade-touched material with this skill in a mage weapon or outfit, would the mage get guard? For that matter, is this something that should be used strictly in a weapon rather than armor?
Also, can someone explain what the materials that promise "30% chance of Masterwork" give you? 30% chance of what occurring?
The fade-touched abilities are completely agnostic. You can put Shield Bash on a Mage's staff, Immolate on a Rogue's armor, or Caltrops on a Warrior's shield. Mix and match, pick your batch, as Dagna would say.
It doesn't matter, as shown above, what gear you put what on. You don't have to put defense on armor and offense on weapons, it doesn't matter. In fact, FT abilities become properties of the character wearing the gear, not of the gear itself. So, for a DW rogue, if you put an on hit Hidden Blades x 4 on the main hand dagger and an increase max stamina +10 on the off hand dagger, it totally doesn't matter if you later switch those daggers to the opposite hands. You still get 10% chance to do x4 Hidden Blades. Doesn't matter which weapon is doing the hitting!
The only thing to watch out for is that you can't stack two identical FT abilities. If you put Hidden Blades x4 on both daggers, it will be as if you only had one. To work around this, make sure that every FT on a character has a different description, even if it is the same type. So Hidden Blades x4 and Hidden Blades x5 is fine, because they are different, you get both.
The 10%, 20%, 30%, etc. stuff is about critical crafting. Basically, it's a gamble. Do you feel lucky? At the end of crafting, it is as if the game rolls percentile dice. If the number rolled (hidden) is equal to or less than percentage number of the FT mat, you get a +10% bonus to all attributes of the weapon. Not sure if it applies to base damage, let's say it does (someone correct me if I'm wrong).
For example, you craft a 100 base damage sword with +20% attack and +10 Dex. If you used a 20% Masterwork, when the crafting is completed, the game rolls percentile dice. If the dice roll is over 20, like 69, nothing happens. You sill have a 100 base damage sword with +20% Att and +10 Dex.
However, if the dice come up below the number, say 17, then each attribute gets a 10% bonus. You end up with a 110 base damage, +22% Att and +11 Dex sword. You win!
You only get one roll per FT mat. Quick save/Quick load doesn't seem to deliver the FT percentage you would expect. At least it didn't when I tried. Either I'm super unlucky, or the game detects you are trying to save scum and adds +99 to your dice roll. 