i think about this all the time.
I think that the more hours you spend training, then the more fish oil you need to take.
Training induces alot of turnover of fat within your body. So for your body to maintain a certain concentration of epa/dha intake has to balanceout what your burning off. This is after you build up to the appropriate levels in your body to begin with.
If your training say 5 hours a week, around 5-6 days per week the period of time your body has to devour fatty acids in your blood is huge. What about your size? Whats the rest of your fat intake like? bf%?
So maybe thinking in terms of "doses" is innapropriate. I like berardis method of just ensureing that around ~30% of your fat intake is polys.
Either way, i refuse to drop below 10g. Sometimes i range upto 15-20g but never fall below 10g. Spread out accross my day, eaten with food.
What about combining them with other fats? ive read that the fats in flax are more easily oxidised then fish oils? Maybe if given together the body would have a substrate to utilise INSTEAD of the fish oils. Not all of them, but less then just fish oil intake.