Tilt-rotor on all 4 motors with an extra twist: the wing shape adds to the lift in vertical mode, so you can use smaller motors, so they're more efficient even in horizontal mode.
> the wing shape adds to the lift in vertical mode
Wings require airspeed to work, which there presumably aren't a lot of in vertical mode.
Tilt-rotor on all 4 motors with an extra twist: the wing shape adds to the lift in vertical mode, so you can use smaller motors, so they're more efficient even in horizontal mode.