Yes I've rendered it at larger size, but then the cloud artefact became more obvious.

You're right, there's some error in it, I have tried to fix it with no success. I even seeded it to see what happen and still am having same error. I think it's due to depth fractal I assigned to the cloud node. And it's perlin too. I thought maybe extreme wrapping was what made it look like that, but playing with it doesn't seem to solve it either. That's when I hate being a n00b. Haha!
At the bright side, hopefully from experimenting with that, I'd know TG2 from inside & outside.

Thank you very much for your feedbacks and suggestions!

Keep 'em coming! Help me be less n00b please. lol