by BorgDog, ref : http://www.vpforums.org/index.php?showtopic=33305&p=329530
So did some more testing. The initial test was with the rubbers at the height the slings were on the default table 35.
If the height is from 28-34 the bounce is not quite the same as the wall, and at 29 the rubber appears to be slightly higher bounce than the wall… BUT at any of these heights after the ball comes to rest is starts rolling side to side by itself until sometimes it nicely launches itself off one side or the other.
At 27 height of the rubber the bounce in as far as I can tell is pretty much the same as the wall bounce wise and the ball stays put after.
At 25-26 the bounce is not quite as high as the wall.