I tried out the Plus EBow a little, and a Fernandes Sustainer guitar extensively. The Plus EBow works, for plain or harmonic feedback, but is cumbersome and can't be toggled nearly as easily as the Sustainer's toggle switch. Small chrome toggle switch 1 has 3 positions, for feedback type. With a modest amount of preamp distortion, fret the biggest string at fret 1, barely striking it.
Different strings have comparable cyclical, unpredictable behavior.
This might depend on the pickup selector as well. The pickups appear to be two humbuckers, nothing in the middle position. I think there is a hidden pickup under the middle of the pickguard. The neck pickup looks unusual. The pickup half closest to the neck has little rectangular metal pole pieces near the string, used to drive the string to create a positive feedback loop.