Mr. Tullamarine,
As usual you're spot on.
Of the three primary constant horizontal flight path states(among many variations), you could trim to with an engine inoperative:
Zero Side Slip: Lowest drag but no way to reliably trim to this state without a yaw string or differential pressure yaw detector.
Zero Wheel: Slightly higher drag than zero side slip but with a positive indication you are there.
Wings level: Highest drag of the three.
For takeoff climbout, zero wheel is the preferred training technique since it's easy to tell when you're there.