Mr. Oswald's actual location in the doorway has been found


At the time these Hughes frames are taken,
-----------------Mr. Oswald is standing over west in the doorway, on the fourth step. He takes a sip of Coke. We see no flesh of his LEFT hand, because he is holding the flag behind him
-----------------A laid-back Mr. Lovelady is SITTING on one of the upper steps, content with getting a glimpse of Pres. Kennedy when he passes right by the building. He has a decent enough view, as there is no one standing in front of him.
But then, without warning, and just as Pres. Kennedy is about to come into Mr. Lovelady's view, Mr. Oswald blocks his view by waving a flag--not up high, but
to his side
An irritated Mr. Lovelady RISES TO HIS FEET in order to see over the flag:

And so, by the time of Altgens & Wiegman, Mr. Lovelady is shown standing over near the center rail of the doorway.