Prototyping Background Visuals for Diver

I'm trying to figure out the look and feel for the new version of Diver. One of the things I really want to get right is the background sky.  I added some logic that lets be vary the sky colors and created the screenshots shown below.

Would love to hear thoughts on these screens. Like them? Don't like them?  Which ones stand out?

Ignore the foreground stuff for now. That's all still very much a work-in-progress.

-Jeff