Not specifically related, but I saw no need to make 2 threads for this.

1) Do double enchanted weapons use more charges per strike? (ie single enchant: 1 charge double enchant: 2 charges?)

2) In order for Soul Trap to work does the weapon enchanted with Soul Trap have to land the killing blow? For example, if I am using a Dagger with Soul Trap in one hand and a Sword with other enchants in the other hand does the dagger have to land the klling blow?

They still use the same amount of charge. Soul trap must be active on the enemy on the killing blow. Soul trap has a duration so as long as you kill them within that duration they will be trapped. With a soul trap enchanted weapon you need not worry since every strike is resetting that duration and placing that effect on the enemy.

Sweet, thanks. I think I'll put Soul Trap and Paralyze on a Daedric Dagger so I can finish them quickly with my sword and save the charges on the Dagger.

soul trap hardly takes any charge but paralyze is one of the most expensive enchantments there is when it comes to uses. you get very few uses from a weapon with paralyze before it needs recharging. but with azura's star it's a deadly if not game ruining combo.

game ruining because it makes everything ridiculously easy if you paralyze everything, trap it's soul, recharge paralyze weapon, rinse and repeat.

You ain't lying about that - I just this instant made it and, wow, I got very few charges from a top-end enchantment.

Yeah, I kinda' figured. I'm just gonna use it if/when I run low on filled soul gems. My magic abilities are low-ish so I run through charges pretty fast.

Magic abilities don't really come into play when it comes to charge size per say. A grand soul gem with a higher level in fire enchantment (as well as perks) will net you more charges and a higher damage then a lesser soul gem with no enchantment perks or low enchantment.

Are you sure? Because someone referenced a long, detailed thread that said (among other things) if you have a Destruction-type enchantement on a weapon you get more out of the charges based on your Destruction magic ability...like with staves.

Well I think destruction in particular can affect that but the majority of where the power comes from (as far as i can see on wikis) is from soul gem type plus your perks in enchanting as well as any fortifiers (like enchanting rings etc.) Fortifiers alone should be more then sufficient to make up for any loss of element enchantments power without destruction perks.

EDIT: Note that destruction enchants are affected by the elemental perks only which is fire frost and shock.

If you wear "fortify " enchantments they will reduce the charges your weapon spends, at least as long as one of the weapon's effects is from that school. I've got absorb stamina and paralyze on my sword and wearing 90% alteration-school cost reduction dramatically reduces charge expenditure.

I may have to do that then because I go through charges way too fast.