Cecil,
before i water i usually lift container to get a feel of how heavy it is , then i water slowly no rush it, i lift again to get a feel of it ,once it feels right then i stop. With the large containers 25g ones i grab the trunk and push it to get a feel for how heavy and easy it is to tip and water until it gets heavy.
Also i water slowly and around and around and around the whole top of container.
Sometimes depending how heavy or light the soil is water can run right thru it and out the bottom holes and root system is still not wet enough.
Even with miracle grow potting soil, shultz and upm i use all 3 i can tell by how light they were before watering then i have a feel by lifting pot how much the soil is wet. After a while you see what i mean if you do this each time, in heat of summer i just use the tree root feeder and water this way it also works good but only for large containers .