soy milk, in regular quantity will be negligible. it would have to be consumed in LARGE doses.
also, you do not really want to mix phytoestrogens, as the weaker of the two seems to win out the ER (estrogen receptor).
If you want to accelerate the growth, the use of a natural progesterone such as micronized wild yam *USP* (USP is a standardized process, regulated). chemical compound of micronized wild yam is pro-progesterone, one of the necessary hormones in females.
Chaste Berry (vitex) has also been purported to be a progesteronic herb.
AS with anything.. everything in moderation.