Anything below the dosage of A314 and/or Instant Shine.
So you could theoritically use 100mcg, as long as you’re using more than 100mcg of a masculine pheromone mix.
I just don’t recommend it alone without a masculine mix, unless you’re OK with experimenting that way.
As far as reasonable dosage goes, I’d say 2.5mcg to 17.5mcg. Pretty small. The influence of TAL is detectable at small levels.