Here are the concentrations you are aiming to add with every dose, roughly:
Traces: .5ppm Fe (assuming CSM+B as being used)
So, using your given 300g of water, and referencing the dosing calculator, we can calculate this schedule:
KNO3: 3x per week, 2.5 tsp + 1/8 tsp resulting in 7.37 ppm, close enough. Or, in grams, weigh out 13.9g.
KH2PO4: 3x per week, 1/4 + 1/8 tsp resulting in 1.29 ppm. Or, again, in grams weigh out 2.1g.
Traces: 3x per week, 2 tsp resulting in 0.49ppm. In grams, 8.7g
With any dosing scheme, watch for deficiencies to crop up, and keep excellent circulation in the tank.