"Our" aproach to yokomenuchi attacking has the Ten-shin movement of the nage (to blend with and avoid being struck by the attack) being matched or mirrored by the uke as well. this makes both of the participants maintain connection from their centers, as well as being in a proper hanmi when movement stops. Nage is blending, but Uke is matching that movement. Both end in a strong centered hanmi , just the opposite foot forward from when they started.
The amount of deviation from the straight-line of attack is mostly determined by how hard the attack comes in...softer, less movement, harder, more movement to dissipate the energy of the blow. (or avoid it altogether).Ma-ai is nice from this as well.
It seems easier with more of a lateral type blow...hay-makers are so much easier to deal with than a good snapping jab.