Brussels, I do something quite similar.
My seedlings go under a t5 fixture with both the red and blue tubes.
Seedlings are grown in a room that is air conditioned to 65 degrees, but under the light is slightly warmer.
Watering is done by standing the 6-pax in a tray and adding just a bit of water to the tray so the soil surface stays quite dry, and I never get sogginess.
Nitrogen is applied in the form of SuperThrive, sometimes just to the point of a slight slight scorch (oops!), starting when seedlings have 2 sets of true leaves.

My female ratio usually comes in at about 2/3.