Took another look at the WWL pattern:
and realized that being NW of them in the Pacific Northwest really gave up much more than 100KW equivalent signal in our direction.
Back in 1964, I remember how weak the signal was for the Cuban-aimed programming, compared to their regular English language programming. Back then, I'd always assumed that WWL was non-directional normally, but went into a Southern pattern for the Cuban broadcasts. Which, of course, did not explain why WWL had such a strong signal compared to other 50KW stations at that distance.
A pattern like this for English and non-directional for the Cuban broadcasts really does explain the difference in signal strengths that I remember, sounding like a more than halving of power.