I have never really tried so I can't say for sure. I am not sure if the ratio of college to HS is hard set for creation of draft players or if it takes into account what is coming out of your feeders. In other words I am not sure if A or B is correct.
A. X% college Y% HS for the pool. So it calculates what your current % is and fills in what is needed.
B. X% college Y% HS of draft eligible players created. So it just fills the other half with the set % meaning you would have more college players than not having feeders.
I suppose you could just create a HS league with equal number of more teams if you want to balance out feeder generated players. It might even answer the age old debate as to if feeders produce more quality players which I don't think has been the case since 11 but I don't think the debate is dead either.