The important question, however, is not which view is Rand's, but which view is more likely true. On this, I think:
a) The flourishing view is much more ethically
plausible. I don't think I would have been impressed with Atlas
Shrugged if the heroes were just centenarians going around reading
actuarial tables to figure out how to maximize their life expectancy.
b) The survival view is more clearly connected to the metaethical
foundations Rand seems to be trying to lay, and the effort to avoid the
is/ought gap. With the flourishing view, it is much more clear that
you're going to have to rely on ethical intuition.