First of all it's best to limit the deck to 30 cards since you absolutely need to draw both the Voodoo Doll and the Rage Potion for your primary damage. Second I'd recommend 3-4 Voodoo Dolls, since you can use up to 3 on a single doll and it will still live to do damage, though the preferred amount is 2 rage potions per doll since it can still take a hit that way (and you won't waste too many cards should it go down).
Even though you mentioned having tried Liquid Shadow and dismissing it I would still like to recommend it. Liquid Shadow on your Voodoo Doll allows more healing than Minor Vampires and will cause your opponent to be poisoned due to the Voodoo effect. Moreover, the Pharaoh and Firefly Queen deck that seem to be troubling you with your current deck can be rendered rather useless by using Liquid Shadow on them, since they will no longer have the ability to summon creatures.
Sample deck including the things I advise:
Hover over cards for details, click for permalink
5f6 5f6 5fb 5fb 5fb 5fb 5fb 5fb 5uk 5uk 5uk 5uk 5uk 5uo 5up 5ur 5uu 5uu 5uu 5uu 5v0 5v0 5v0 5v0 606 606 606 606 606 606 8po