Since you think you can keep up with weekly water changes initially, you can use that period to find out how much you can reduce the dosages without adversely affecting the plants. Start with the dosages per the table. Let the plants grow for 2-3 weeks to see how they do with what you know is plenty of each nutrient. Then reduce the KNO3 dose by about 25%, and watch to see if the plants continue to grow equally well for another week. If they do, reduce the dosage to half the table amount and watch for another week. If they continue to do well, drop the KH2PO4 dosage in half and repeat the observations. If they continue to do well, drop the trace mix dosage in half and and repeat. If they still do well, you can just use half the table amounts, and you should have no problems doing 50% water changes every two weeks. If your plant mass in the tank gets much higher, or if you add CO2, you will want to repeat the above because the plants will be needing a higher dosage then.
The reason for starting with the full dosages is to see what the plants look like when they are not limited in growth by any of the nutrients. This lets you judge what their growth is like when you restrict the amount of nutrients.