How many liters (or gallons) is your watering can? I think that Akerne means full strength to be about 100 ppm N.
The special situation you have is a very long dwell time of the fertilizer solution with your roots because the roots are in contact with the solution for a long time. There may even be continued wicking up to roots during the week, correct? Compare that to my pot full of LECA through which percolate fertilizer solution. What contacts the roots absorbs into the velum but everything else flows out the pot. There is no continuing reservoir. I probably need a higher concentration of fertilizer than you do.
The special situation you have is a very long dwell time of the fertilizer solution with your roots because the roots are in contact with the solution for a long time. There may even be continued wicking up to roots during the week, correct? Compare that to my pot full of LECA through which percolate fertilizer solution. What contacts the roots absorbs into the velum but everything else flows out the pot. There is no continuing reservoir. I probably need a higher concentration of fertilizer than you do.