Those 2 men that Bowers saw “in line” with the Triple U bridge, preceding the shooting yet not AT the time of shooting , could be that they had either left or were not in LOS of Bowers anymore. That suggests the possibility of a shooter and his accomplice located at the far storm drain at the junction of the wooden fence and the concrete bridge abutment.
The shooter could have arrived at the far storm sewer by access to an unguarded larger diameter drain pipe that exited near the stream that ran some distance beyond the parking lot.
This is about the only probable place that a shooter fairing at the front of the limo, could have had the angle to bypass the limo Front windshield and JCs head.
It’s about the only probable way a shot from the front could strike the right temple of JFK where the “V” wound is in the autopsy photo, the bullet then traverses across the right side of the skull causing the radial fragmentation lines visible in the JFK lateral skull x-Ray, and without any damage to the left side of of JFK skull, and the exit wound in back of the head still be to the right side the longitudinal centerline of the skull.
There were many cars parked along behind the wooden fence in line all the way to this far storm sewer location which could have provided cover from LOS from the tower position Bowers was viewing the parking lot from.
So one gunman at ground level actually standing in the sewer would have a plausible prone position to fire from thru just a small gap in the wooden fence section, and taking advantage of ground foliage ti obscure barrel yet allow a view thru the scope with clear LOS to JFK at about Z313.