Driven by a personal dilemma, I posed a question online about when is it best to post stories (something we've discussed on the site many times (years ago)).
After quite a few responses, it turns out: it don't matter. Between the 2 to 5 day limit ("Free" vs. "Premium") limit on "New" and "Updated" story lists and the RSS feeds, it really doesn't matter, even though there IS a definite 7+ hour delay in the automated posting vs. waiting to post after SOL shuts down for the evening (though the same delay doesn't seem to apply to posting during the day).
As I suspected, most readers are either retired, disabled or both, and read throughout the day, but they can easily access the story whenever they want. I still believe in posting on specific days (specifically avoiding posting on Saturdays, since you get bumped off the "New Stories" page almost immediately), but the actual posting time doesn't seem to impact readers much.