Should the clubface be in line with the left forearm? Facing the sky? or toe down? or somewhere else? at the top.
The issue isn't where is the clubface is at the top of the backstroke because its not important,
the issue is that the
clubface has been set with a relationship to the left wrist and this is maintained through a
consistent hold without grip any slippage and they
respond to the mass/weight of the clubhead moving with relation to the overtaking caused by the de-acceleration phase of backstroke with the arm and the acceleration which you create by the maintaining a rigidity/torsion of the left wrist during the initial acceleration from address which means that your hands are moving in accordance to physics instead of creating additional movements.
Do you want to be a golfer that moves according to what is most simple and natural or do you want to be the golfer who wants to add complications?