I used the term parallel down the line because if the shaft is parallel to the target line then the angle between lead arm and shaft is probably very close to what it appears to be. If the shaft is not parallel to the target line then the angle could be considerably distorted.

Do the ams that you mention have the same (as good) of trail arm position as Palmer has here?

There is a relation to swing plane that has an effect on the angle I think. Possibly the flatter the plane the more obtuse the angle between lead arm and shaft at this point in the swing...