Wow--another post-birthday treat for me with this thread. Heather, those snaps are GORGEOUS! I agree about Intrator's use of close-ups--one of the *many* reasons why I adore this movie!
Believe it or not, the filming happened around November 1960 (which made Meg Myles' swim sequence a frosty event for the actress). That means GH was 37 when she did this.
There's a video kicking around fandom of an episode of an early 1950s TV show, Lights Out, in which she had a non-speaking role (but got some good close-ups). She more than once described herself as a teenager "longing to play the ingenue but stuck with a whiskey-baritone voice... no boobs, no bottom" (I'm only half paraphrasing here). Even in the early 1940s when she was doing summer stock, she was playing vampy, older woman roles.
G.