Everything (except slipping and spin entry) is done in balance. Keeping the aircraft in balance is a requirement from exercise 4.
Lookout
Attitude
Instrument
Please note that "Instrument" is singular. That part of the scan is not designed to be a full pannel scan but a brief check on 1 instrument and then while looking out again, decide if what was seen is corect or requires something to be done.
Taking a 0.2 second glance at the ball is not going to cause a major issue.
I teach how to maintain the turn and then teach the entry and exit.
The entry is simply;
"From straight and level flight select the turning attitude while keeping the aircraft in balance and altitude constant"
The exit is simply;
"From level turning flight select the straight and level attitude while keeping the aircraft in balance and altitude constant"
I would not subscribe to trying to tell the student in the air that ;
Rudder must be applied now because of adverse yaw.
Rudder must be applied now due to a change in power.
Rudder must be applied now due to a change in airspeed.
Far simpler to get it straight from the start - in all cases;
Rudder must be applied to maintain balanced flight. i.e. keep the ball in the middle. Who cares why it is not in the middle just kick it back in there or better still never let it out of the cage!!
Initially teaching the outside view, control pressures and then refining the accuracy with a glance at the ball / altimeter.