I would say it would work either way, providing you mount the led strip so that it appears in the mirror the same as it would at the top center of a normal monitor. You can use a CCD camera to view the IR led strip lights to make sure you have them mounted correctly behind tinted glass. My Aimtracks will calibrate and work fine in the complete absence of a monitor, so they don't care what orientation the screen is, as long as they see their senor bar with the single led on the right. The only thing that would mess with it being a reflection, is if the mirror was only a half mirror. You could mount the led strip anywhere else on the cabinet and as long as the Aimtraks can "see" it, they will calibrate.