Dudley Henriques schrieb:

Once the turn is established and sustained, I see no way to check
coordination by looking at the nose.

"The pin won't stay there long, but long enough to establish control
pressure application
quality."

When starting the turn, you roll, which means you apply ailerons. When
the turn is established, you don't apply ailerons anymore (how much
exactly depends on the aircraft, some even require outwards ailerons to
prevent overbanking). Hence the "pressure application quality" you
establish at the beginning of the turn doesn't do you any good to stay
coordinaed once the turn is established.

Stefan