I ended up settling on settings:

 '(font-lock-maximum-decoration (quote ((c++-mode . 2))))
 '(scroll-conservatively 101)
 '(scroll-margin 4)

and in the C++ mode hook:

  (setq jit-lock-defer-time 0.01)

So I am able to scroll through C++ buffers with timely redisplays and
without recenterings. Closing.