I'm still working on this myself. Eve took 1,000 mg flax and 800 mg oats. I started out at very high doses, but now I'm aiming for 3,000 mg:
http://www.breastnexus.com/showthread.php?tid=8419&pid=41127#pid41127
The comparison I made with hops is just to correct for the different amounts of phyto-estrogens in different herbs. I want to stay away from the stalling dose of flax.
The one that really needs to be proportional to oats is flax. Flax increases SHBG, as does age, so I take equal amounts, instead of more flax, like Eve. You need to correct for the fish oil.
Taking only oats or only flax swings SHBG around too much. This is my third experiment with flax and oats already, it takes quit a bit of tuning. My reasoning is like this: I take the flax as a phyto-estrogen, so I align the dose with hops for equal amounts of phyto-estrogens. But then the flax increases SHBG, so I take an equal dose of oats, to lower SHBG.
If I get too much SHBG, my growth will slow, because there will be no free testosterone for aromatase to make estrogens from. If SHBG becomes too low, it will not bind DHT, so I may break out or lose hair. It takes time to change the SHBG level, so these are slow experiments.