In my experience a well balanced and any rudder coupling mixed out you can do length of the field knife edge passes with no gyro even installed. Of course all airplanes/jets are not created equal so some are going to be easier to do that with in my opinion. The gyro would help with smoothing things out if windy/bumpy conditions,I have flown most of the gyros out there and they differ a bit. The Igyro 3E can be flown in hold because it leaves the rudder in a normal rate mode,so basically just have the ailerons and elevator in hold. Also the Spektrum AS3X/AS3000 you can turn on hold for ail/ele and rudder stays in rate mode, I’ve used the Cortex in hold messing around with hovering/torque rolls but didn’t use it for normal flight.
You could get lined up and turn hold on for a knife edge pass, but would still require an aircraft balanced and trimmed well and then not sure would hold that hands off without a super high gain.