Interesting you mention that, Jed. We have discussed it before. The day you had was intentionally slow as you described and understandly time very well-spent.
But at the risk of offending Mr. Huntley.... and Jay Flemma... and I know you said Dunes..... but it brings to mind...
I don't think the Shore course was designed with speed of play in mind, let's just say. Bottlenecks occur quite often, at least two different points. I have never figured out WHY, but I think Mr. Huntley can concur that at darn near each par three after #3, there is typically some sort of backup, with the worst happening on #7. No round there is anything less than great fun, but I have also yet to play a round there that didn't take a lot longer than those on other courses.
So perhaps here is a course where architecture factors in.
TH