Skybox has visible texture seams

[Acies]

You are a boss! Your post made me really happy. I dedicate this to you:

"Champion"

Author Unknown

The average runner runs
until the breath in him is gone,
But the champion has the iron will
that makes him carry on.

For the rest the average runner begs
when limp his muscles grow,
But the champion runs on leaden legs,
his courage makes him go.

The average man's complacent
when he's done his best to score,
But the champion does his best,
and then he does a little more.

I am assuming you are rendering with a 90 degrees horisontal FOV in Terragen. I think cubemapgen has some sort of option for edge adjustments, called "Edge fixup" - might be something with that. If that doesn't solve it you can send me your raw renders and I'll test around some.

Your setting looks really nice!