The highest point is over the centre but not the centre that we believe there is, as in the north pole because that's just the outer part of the inner centre or the bottom of the hump, or to be more clear, the Earth is much like a manual orange squeezer.
Double it.
My thoughts are that the earth is like 1 orange squeezer where we stand and 1 inverted squeezer directly above it pointing down.
I don't know if any flat earthers believe in this dome idea, but if so, maybe they could explain this ?
Back up a bit and start with what we know.
We know the sun's path varies. The sun rises up and down as well as in and out as it turns above the earth.
My guess is that the shape and dimensions of the "dome" must vary as the sun moves inside.
I am also of the opinion that the internal structure of the "dome" resembles a hollow donut or an inner tube --- but not exactly. Imagine inflating/deflating the inner tube until the inner ring compresses and expands, fusing and unfusing, opening and closing with the motion of the sun.
N.B.: I use the term "dome" to refer to the reflective surface only.
I am not advocating for the firmament nor anything beyond the reflective "surface" so to speak.
For example, how high is the dome over the North Pole ?
My guess is that it is 1 of the lower points on the dome.
It seems most likely that the North Pole is actually the base of a huge stalagmite and up above is a huge frozen stalagtite hanging above our heads. The stars we see are a result of the sun's rays passing through both of them. The bubbles and or inclusions create the illusion of celestial bodies.
In reality, when we look up at the night's sky, we are seeing the same thing we see flashing in discotheques. However, we get it from 1 medium above and 1 medium below.
How high over the southern tip of South America or Africa ?
Over the Equator ?
Irrelevent.