1) water fully -- use as much water to get the job done. full saturation is the goal. dry pockets are bad
2) wait for some minimum drying before repeating. If you re-irrigated at same loss of weight, it requires the same volume of water.
sounds like you are choosing a volume or whimsically choosing to when to water based on things unrelated to the plant. Fix these habits first. in a high water capacity substrate, wait until top 1" deep dries. in something like coco, you water when the top layer starts to change color. Becoming familiar with the weight at this point can make things easier. Give a little lift and you know when to water.