they are more than likely going to outgrow that box. Even with LST.
easy fix is to get another rubbermaid tub the same and flip it upside down on top. Doubles your height instantly.

LST is best done at 5 nodes.

Log your watering, make it a daily routine, take a ruler and measure growth. Learn from your first grow. Clone the plant before flowering and remember that log, cause the clone will grow at the same rate.