peddroelm: Yes kill effects work best vs lower level enemies. Why on earth would I want to insta-kill low threat (lower level much lower threat) punchbags I can train combat skills against instead ? I hate the passive kill skills and effect on weapons with a passion.
That may be fine if the encounter is against a reasonably small number of relatively harmless low level enemies, but that is not always the case. In particular, here are some cases that come up:
* Encounter is against a hoard of Rapax, many of them low level (but with high HP). These Rapax can have a lot of HP, causing the battle to take a rather long time, risking exhausting your resources, and even lower level Rapax can do significant damage. Also, maybe there are other enemies that are serious threats; getting rid of the lower level ones allows you to focus on higher level ones. One thing to note is that you can't save during battle, which can be a problem if you need to go somewhere or get unlucky toward the end of the fight.
* Encounter includes some powerful enemies, and they start summoning elementals. Elementals may be a low level, but they can hit really hard with their physical attacks, and they have a lot of HP. In this case, you *will* want to disable them as soon as possible, and an instant kill spell works well here. (Also, note that elementals are weak against the opposite element, and the only element they have high resistance to is their own, so spells tend to work well on them; I happen to like using Turncoat on them.)
Remember, low level doesn't always mean low threat, and prolonging a fight is not a good idea if some of the enemies are dangerous.
peddroelm: On dual class - since in my entire Wiz8 career I have never bothered to multiclass once I wasn't very curios about it.
As a starting point I would guess it would sum say number of warrior lvls * warrior contant + number of gadgeteer levels * gadgeteer constant + nr of caster level * caster levels.. But you'd have to test it to make certain ..
Same for hitpoints HP for 5 levels of fighter with X vit + HP for 6 levels of alchemist with X vit + ...
To me, I find that I want to know *all* the mechanics, not just the ones that come up with my playstyle; it might give me new ideas, for one, or it could lead to an exploitable glitch.
For HP, the way it seems to work is as follows:
Base HP is the sum of the Base HP gained from all class levels, plus the Base HP gained from the first level up (in other words, the first level counts twice), minus any that have been drained or lost forever. Vitality modifies this amount. (Note that I may be off on the mechanics of drained/lost hit points, since I avoid losing HP to disease and I always cure Draining (which is quite rare) before the next level up.)
One thing to test: Consider these two characters:
1. Starts as a Priest, changes to Lord at level 2.
2. Starts as a Lord, changes to Priest at level 2.
Do 1 and 2 have the same Attack Rating at level 2? I note that 2 has more HP, but 1 gets spells earlier (and if both characters level only as Lord from then on, will get one more spell pick total).
Edit: One more thing. When testing expert skills, make sure that the character has unlocked the skill normally; if you get the skill from an item, or if you hack the skill without changing the stat to 100, the skill will not provide any benefit.