Let the pot dry to the point that the plant wilts. Then water 1 day before the wilt. lift pot for weight to know when dry. use moiture meter when dry. All theses ways you can learn when to water.
1 or 2 plants under a big light you will get more then 3 oz. In a grow with severa;l plants its 3 oz is average. Out doors ya can get pounds from 1 plant.
Go ahead and flush the plants with a high volume of water. After that then water with plain water. You will rinse out nutes and give the plant time to use it up left over nutes.
The last time i heard rooting gel is for clones.
Now don't quote me on this. Its what i heard.
You may have to go advanced with this question.
I'm subcribing too.