abuse R1 and L1 that freezes the action while you change weapons and plasmids.
I personally used electric shotgun shells to stun them, then switch to the grenade launcher and blow them away and switch back and forth
although for the first Big Daddy i don't think you had those yet.
At this point I have very few electric shotgun shells. No grenade launcher. I'd use the electric plasmid but, I can only equip 2 plasmids, I have incinerate and telekinesis, and I don't think I can unequip either to re-equip electric, so that kind of sucks. Thanks for the tips though, I'll remember that for future Big Daddies if I get that far, heh.
I came real close a few times, had to take a break for a bit though.
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Formally Ikon.
Indie Gaming Board: http://www.gamefaqs.com/boards/293-indie-gaming