Sorry that the people with a small budget and only free time are not doing it for you. Please go show them how it is done.

40-50 miles equals about 1500 feet of drop along the supposed curvature. I don't know any light house that is place 1500 feet above sea level. So, if your numbers are correct, then the conclusion is we live on an earth where the radius is much larger, or its concave, or its flat or we don't know how light travels.