So, I think the answer to the original question is as follows:
If Universal Graviation is correct then objects far from the centre of the Earth should be attracted less strongly to the centre of the Earth than objects near the centre. On a round Earth this is not a problem since for the most part all objects are about the same distance from the centre.
On a thin flat Earth, however, rimward objects are much farther from the centre than hubwards objects, so the weights of things should drop drastically as they move rimwards.
However, the weights of objects do not drop drastically as they move rimwards, so either universal gravity is false, or the Earth is round.
So, if you believe the EArth is flat then universal gravity must be wrong.
Well, that was the purpose of my questions, why the FE theory doesn't seem to make sense when taking into account gravity. If you were at the edge of the "disc", so to speak, a plumb bob would hang not straight down, but at an angle towards the center of the disc Earth, since most of the mass is there. This obviously doesn't happen.
So, as you say, we're presented with the choice, either 1) Pick traditional gravity with a sphere Earth or 2) Pick no gravity with a Flat Earth. When presented with those two choices, if we do not let our bias guide us and rely strictly on observation and the scientific method, (and common sense), we see, from such experiments as Maskelynes, that we can show situations where gravity, and not an accelerating Earth, explain observed phenomena.
It's one thing to quest for the truth, it's another to ignore the obvious.