My understanding is that it very much depends on the system. Are you flowing through rockwool or rocks? Coir? Perlite? Pots or slabs (like rockwool)? I don't have your answer, but I think this stuff is going to make a difference. The higher your flow rate the lower your concentration would need to be, right? If the roots are in a saturated medium that holds water well versus a continuous drip in a rock or hydroton system, it stands to reason that you would need to take that difference into account. I'm just speculating, though.

General hydroponics has feed schedules based on recirculating vs. drain to waste. It won't exactly answer your question, but it might give you a good relationship for comparison.

Here is a link that might be useful: GH Feed Schedules