I have an LS8-18 and an SZD-59.
I use suction cups to mount the cameras on the canopies for more than five years.
I clean the canopy and the suction cup before mounting the suction cup.
I remove the suction cup at the end of each day of flying.
No damage.
No circular rings.
No crazing.
No distortion in the optics.
I apply my saliva to the rim of the suction cup before mounting.
No decay or periodontal disease has been detected, either.