Since your tank is only lightly planted at this time I would stick to the 40-60 gallon dosing range for the time being, as you add more plants to the tank you can slowly move to 60-80 dosing... The reason is you don't want excess nutrients in the water because it'll promote algae growth, as the tank start to fill in with more plants they'll need more nutrients available... But until it does I would stay on the lighter side of things.
Tank looks good by the way!!!