Earlier we proposed a new type of dielectric anisotropic protective coating for Brewster-angle windows (BAW) that retain both the position of the Brewster angle and the true zero of the substrate's reflection factor for p-polarized light [1]. The useful property of such coatings consists in the independence of their optical quality from their thickness and this makes them less sensitive to surface damage. On the other hand, by adjusting their thickness one can influence the reflection of the s-polarized light. Here we will show that for any given substrate one can choose a certain value of the horizontal tensor component of the negative anisotropic coating film and then, by adjusting the him's thickness, reduce to zero the reflection factor for s-polarized light as well. In the region of positive anisotropy the same optical thickness of a film maximizes the s-polarized light reflectance which may be much greater than that of a clean substrate. Both these variants may be useful under adoption of BAW in resonant laser systems for second and higher harmonic generation.