With your background in web development have you read things like Krug's Don't Make Me Think and William's The Non-Designer's Design Book? These are focused more on the design aspect of web however they contain some good underlying principles for data visualization as well.
Tufte's book are all great for underlying principles even though, as you noted, they aren't focused on modern technologies. Beautiful Evidence from 2006 has some updated thoughts but he still borrows heavily from his earlier books.
For general multimedia concepts, Mayer's Multimedia Learning is good from a human learning perspective (my background).
I found Data Points: Visualization That Means Something to be a good modern guide.
From my perspective, I am glad you are looking down the road and recognizing that after the data are analyzed the analysis must be communicated.
This is all kinds of useful. Thanks!
You can learn an astonishing amount about web development without ever having to think about how it'll look to another human being. In a professional context, I know enough to realise when I should hand it over to a specialist, but I won't always have that luxury.
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