Thanks, guys. You're all very correct about the details. As for the math, so far it checks out more or less with my other "sources"
Anyway, I'm being careful about the details not overriding characters and not info-dumping on the audience. I'm asking for help with the world-building because that's my weakness. So thanks for the help, and advice, maybe I'll post some of my manuscript when it's done for critiquing.

As the author, I need to know as many details as I can, so that I can present the world matter-of-factly, without being opaque about it. The more I know, the less I have to explicitly say, if that makes any sense.
I'm not a slave to the math, but the reality is that a culture bases itself on the world around it, so a midday eclipse of 1.5 hours makes a big difference for a developing culture. That makes for story ideas and interesting characters often enough.

Tomohawk, good points on not defining the exact universe...I'll try not to worry about it too much.

So far, the reasonably-accurate world (not perfect but who cares), is an earth-like planet orbiting a strikingly blue gas giant at approximately 400000 thousand km, with an orbital day of 30 hours, and (for the near side) a daytime eclipse of about 1.5 hours for the giant's 18 degrees of angular diameter. The nightime is dominated by the blue giant, making it almost as bright as the day. Cool part: the slightly lopsided orbit brings the moon slightly outside the giant's magnetosphere once every time the moon's orbit precesses. This makes for a "new year" marked by nearly planetwide aurora. Awesome.

If anyone has any further thoughts, I'd love to hear them.
Thanks bunches for the help, guys!