As I see it, "shomenuchi" refers to a strike to the top of the head while "shomenate" refers to the more linear strike to the front of the head/face.
Shomenuchi is pretty much a useless way to attack someone empty handed but we can learn some things from training with it as an attack.
Shomenate, OTH, can be a very quick and effective attack. Sometimes we like to bring it from down low as a palm strike to the chin. Is that still shomenate or is that drifting into the relm of tsuki?
Thanks, I suppose my confusion was down to the fact that we tend to just refer to shomenate as shomenuchi too, the idea being that the initial movement creates space before the attackers hand comes down again from the top toward the attackers head. Options to strike are available anywhere along this arc obviously so I suppose the naming convention we tend to use comes from the last part.
PS - Surely everything drifts into the realm of tsuki eventually