I'm not sure the Guardian is a perfect answer, but it has possibilities. The question is, do you expect it to keep you out of trouble for a few brief seconds while you get the other engine throttled back, or are you expecting it to provide enough control to permit continued flight on one dead engine ?

In simple rate damping mode (what they call 3D), but with heading lock disabled, the Guardian should buy you some time by slowing down the initial response to power loss. But if you have heading lock enabled in 3D mode, then the Guardian may or may not be your friend. Depending on the aerodynamics of your particular airplane and how you have your Guardian response set up, yaw toward the dead engine could be exaggerated due to adverse yaw from aileron input.

In 3D mode, my understanding of the Guardian is that it will try to keep pitch, roll and yaw attitudes level unless you make a control input. If the airplane begins to yaw and roll into the dead engine and you have no stick input, the system will try to keep you straight and level. But does it use aileron or rudder (or both) to keep your wings level and on the original heading ? And how would your airplane respond to an aileron correction in the presence of a strong yawing tendency ? I think a lot would depend on the particular aerodynamics of your airplane and also on the way the Guardian's many features are set up.

Bottom line is that the Guardian may be a great help, but will require some special testing and adjustments to tune it to your airplane. Unfortunately, the testing could cost you a few airplanes in the process.

Dick