you can definitely pick it up on invoker (quas regen is more than sufficient when you're not last hitting w/ exort), or maybe SF to get those first couple last hits without razing but idk..it feels bad if you have to use it early bc your dmg is gone.
BUT 2 branches and tangoes (2 dmg, 460hp regen) VS 3 faerie fires (6 dmg, 225hp regen) is priced equally.
for a bottle rush build like the current sf, it might not be too terrible. by the time you get your bottle theres probably no chance you had to use all 3 of them and you've probably made it to lvl 2 and are earning souls.
dunno. i think there are too many variables and if you're the kind of player that knows that its good for bottle rushing mid AND you're confident that you can adjust accordingly, i doubt you'd be reading a guide.