Yeah, no sense in putting the sticky side towards the mobo.
However, if mounted upright in a case these plates only stick to the tray with light heatsinks, such as the stock coolers. I tried to stick them to the tray with the HR-01's mounted but they are way too heavy, board bending is inevitable unless you screw them heavy heatsinks onto the mb tray.
Next time I'm gonna use water, EK supreme + supplied metal clips from the Z7S should work just fine as backplates, and no mounting trouble.