I am thinking that the only difference between "gap" shooting and "split vision" is where you are aiming. Your eyes cannot focus on several spots in different distances all at the same time.
In gap, you look at the point of your arrow and put that point on a target, which is 10", 15" etc UNDER or OVER what you actually want to hit (except at point-on range). This is described very well in several posts.
In "split vision", you are doing the very same thing, but you are concentrating not on the "target" but on what you are trying to hit, example, the deer's chest. In the mean time, in your peripheral vision, you still see that arrow point and you see that it is in about the correct position for that shot.
When you are taking long shots, like HH's 150 yard plus shot, you have a target located above the animal, likely you can't even see the animal because it is covered by your bow hand.
You need to choose a target that works. Like, the top of that evergreen tree lined up behind the animal, or that rock further up the hill. If that shot is too short, you pick a farther, higher, taller target, and vice versa for if you shot too high.
With enough arrows, and good form, you should be able to walk the arrow in, as long as the animal doesn't move, which means starting over with your targets.
With things such as string walking (moving your arrow hand position along the string, to known spots) and face walking (moving your anchor point up and down your face, and by extension, right down your chest), you can greatly expand and fine tune your gap shooting.
With "instinctive", which is just a name,(you don't instinctively know how to do this, but you learn)you are actually using a much coarser style of gap shooting. You don't actually put the point on anything, and you don't consciously think of range, you just train and learn what the sight picture needs to look like to work for any given shot.
ChuckC