Of course it's not going to be easy to get a controlled invironment for the experiment and of course there is the bendy light problem.. but what I'm wondering is;
if these differences in distances would be accurately measurable (and I think it could be) does this not create a way to determine whether gravitation-like effects are caused by a force toward the centre of a globe, or a force that is uniformy divided over the surface? That would finally be a wonderful and repeatable way to see who's right. Which is what most of these threads on this forum are about, right?
Now if we can first agree if the theory checks out; then we can worry about the practical conditions to actually try this in reality.
PS: about bendy light; do the experiment with the tops of the two pillars at 30 metres from the surface and use a laser to determine the distance (oh no.. but bendy light will make light behave differently at the bottom of the pillars then at the top altitude) and then: do the same experiment with two pillars at 60 metres above the surface where a ball is dropped till a point 30 metres lower, so the bottoms are now at the same altitude as the tops were in the first experiment.. that way, the 30 metre altitude laser beam becomes a constant, even if light bends..
(Please don't troll about the 30 metres number; we're all smart enough to understand that this theory also applies to 10 metres, 100 metres, or whatever relative dimensions)