But still 15-20 females is still 15-20 plants if you dont even consider clones. I would start like 10 at a time.... pick the best pheno's clone em and rock it out.....
But 30 plants yeah you should totally hit 200-300 pounds for sure dude!!!
It all depends of the skill levels involved to really make sense of this equation and therefore asking such a question warrants no skills involved .. Hence this makes me come to the conclusion that the 30 seeds may become nothing but another grow gone wrong ..