Glare is a function of the aiming angle or in scientific terms; the angle of incidence. See the image which illustrates the angle of incidence on a flat surface. The same holds true when lighting art on a wall. The best you can do is to change the position of the light either forward, back, left or right to redirect the glare to the least viewed area. Left or right pitches the glare to the opposite side of the room. Objects above eye level are the most challenging of all art lighting applications. It is very difficult to eliminate glare from all angles.
To test for glare on your art, get a ladder and a flashlight. Have someone help you try several positions in the room while you observe the glare from various positions in the room. When you can see the flashlight image in the glass you know that is the angle of incidence. Our projector is design for offset mounting to specifically address reflected glare and still maintain the masked area of light.