If I am starving, how much Jello should I eat? That is what your question seems like. Plants need nitrates, phosphates, potassium, trace elements and a source of carbon, preferably CO2. They also need enough calcium and magnesium in the water to meet their needs, so very low GH water often needs additional calcium and/or magnesium.
If you go to the sticky on dosing methods you will find good advice for how much of what to dose. Just don't forget that pressurized CO2 is essential, especially for that big a tank and that much light.
I assume your light will be 4 x 65 watt PC lights? If so, you will have high light intensity, assuming good reflectors on the light fixtures.