Probably real gas giants arent translucent sice most of their gases are Not traslucent. But in Bespin we can see that most of its gas is oxygen. I dont mean it should be "sunset" all the time, but light would go through, or at least sunsets (and sunrises) would last MUCH more hours that it does on earth.

Anyway i was trying to go to an extreme. Wich i mean is that you shouldnt care too much about what would the sky look like on sunrise or sunset when you are talking about a "giant tibanna gas planet".