Fair enough. According to the RE model, the value of g would be 10% less than the value at the surface of the Earth at a height of 565,000 ft = 107 mi. Since we cannot measure g with a higher precision than 5% with amateur equipment, we must go this high to get a conclusive result. Also, due to the Moon's tidal effect, as well as the rotation of the Earth itself, the value of g is not just dependent on the position, but also on time.
Nevertheless, due you claim that there should not be any variation in g with altitude?