Checking for trichome color is de rigour yet different buds will mature sooner, specifically those at the top first. The Buds aren't very full to my eye but the trichs will tell for sure. By taking those buds at the peak of their ripeness you assure a very consistent maximization of yield. The nutrient uptake at this point is close to the maximum possible and you may actually excede the 2000ppm that is considered the maximum <C> of nutes. This must be a happy time for you, your sense of anticipation is obvious. Oh <C> is the standard abreviation of concentration