and also keep the nose straigh in the roll using rudder! some extra rudder is also helpful to increase rollrate.
A barrel roll is not a fast roll rate manoeuvre.
However, rudder is useful when executing a Derry turn, but one must be very careful at 500 feet AGL, especially when the transition from +6g to -3g must be made within half a second.
One feels that it is now time to retire from this thread.......exit with full loop away from crowdline at 90 degrees until no longer visible.