The only way that Givens story would make any sense at all is if Arnold Rowland made up his pre event sighting of a man at the SE window 6th floor TSBD.
Because if Oswald was originally planning to shoot from SW window , he would not have been at the SE preparing the SE window 3 stacked boxes when Givens saw him at about 11:55.
So the 3 boxes would have to been placed only after Oswald had gone to SW window at 12:15 and saw Bonnie Ray Williams which prompted Oswald to quickly retreat from the SW window.
I have a viable scenario for Oswald as the 6th floor shooter only if I can have some variation of timing allowed for Mrs Garner, Carolyn Arnold, and allowance for the 2nd half of Arnold Rowlands story of sighting the “elderly black man” at SW window at 12:15 as being a post event mistaken memory of seeing Harold Norman with dust in his hair.
Also I need a minute or more for the Bronson film starting at 12:26 or 12:27 rather than 12:25. I think is possible because it’s not CERTAIN that the Bronson film begins at 12:25.
Then the shooting sequence I use is Dans Z223 1st shot hit , Z313 2nd shot hit and 3rd shot 2.5 secs after Z313 as a “celebration” or “exclamation” shot fired unaimed because Oswald was a Kook. This fits with the 1….2.3 pattern , is about only 6.5 sec for all 3 shots with fits close enough to Harold Norman’s 4-5 sec recall as well as the general witness perception of 3 shots fired rapidly.