Another thing worth adding -- which actually might go further to answering the original question -- is that a tennis ball that strikes a "slow" surface obliquely can have a CoR as high as 0.9, which means slow courts can be "fast" in the vertical direction!
A rebound of 53 inches corresponds to a CoR of 0.73; a rebound of 58 inches corresponds to a CoR of 0.76. But of course those figures are for the ball-surface system, not just the ball and not just the surface. Hence, the surface CoRs cited in the previous posts seem about right.
If you...