Light Scattering Concerns

The obvious concerns are Rayleigh and Mie scattering. Rayleigh scattering peaks at angles normal to the beam direction, and is proportional to the inverse of the fourth power of wavelength, so blue scattering is much more than the rest of the visible spectrum. So a huge beam of sunlight will also be visible in the blue from the side view.
Mie scattering is off of particles, not N2 or O2 molecules. The degree of scattering relates to particle size and shape, so there can be some uncertainty in a predictable behavior, with or without clouds.

Lots of concerns here.