Another thing to think about is how the concentration of nutrients changes over time as you continue to feed. The plant will use only some of the nutrients that you feed it with, and not as much of others, so if you continue to feed full strength for more than ~1 month then you will always start to see burn, even if the plant was ok with the nutrient concentration at first because the rate of consumption of different nutrients is not the same. Also, as the medium dries out, the concentration of the nutrients will increase, so don't let things get too dry.
The solution for this is to flush your plant with plain water every 2-3 waterings (always feed normally right after flushing). Another thing that will help avoid nutrient overconcentration is to feed your plants with excess solution, until there is ~30% runoff out the bottom (I do 1 gallon per plant for each watering). You can't overwater coco if the drainage is good. I use about 70/30 coco/perlite.
You definitely need to keep an eye on the pH (I go for 6.1-6.4), and also the EC (0.6-0.8 is safe), in order to reliably take care of the plants over a long period. Also important is to collect some of the runoff and test it to see what the conditions are like in the root area. Often, the pH there will progressively get lower into the 5.7-5.8 range as the nutrients concentrate over time if you don't flush. Too low or high and certain nutrients like Mg will not be able to be absorbed and you will see deficiencies.
