r^2 is not that relevant. The moon is 384,400 km from the earth and can cause a total solar eclipse despite only being 3,474 km wide where the earth is 12,742 km wide.
The geometry works out more or less linearly with distance. So 1.5 / 0.384 = 1.065. Which means and object 1.065x as wide as the earth would also provide a total solar eclipse. Making sunshades more than 2x effective L1 vs LEO.
PS: Only 1/2 the time they are on the sun facing side, but they are not perpendicular with sunlight for that entire half. At a 45 degree angle a sunshade blocks ~70% as much sunlight vs a 0 degree angle.
The geometry works out more or less linearly with distance. So 1.5 / 0.384 = 1.065. Which means and object 1.065x as wide as the earth would also provide a total solar eclipse. Making sunshades more than 2x effective L1 vs LEO.
PS: Only 1/2 the time they are on the sun facing side, but they are not perpendicular with sunlight for that entire half. At a 45 degree angle a sunshade blocks ~70% as much sunlight vs a 0 degree angle.