The RP06 maintenance manual says
Emergency Retract. An emergency retract operation is used to remove
the heads from the pack if the retract operation fails, or if there is
a power or power supply failure.
188.8.131.52 Emergency Retract Mode
Only one positioning operation can occur in this mode, this being an emergency-retract operation. In the
Nemesis' Bonzo Doo Dah and Richard Monteiro's FastForm/BigK in Amstrad Action Issue 16 gave somewhere between 203 – 206 K per side, leaving one or two standard tracks for a small boot stub to load up the custom disk parameters.
Both of these hit all three of your parameters: all they did was modify some settings held in RAM. I was a dedicated user of Bonzo ...