Quote - A bit of confusion... I'm not looking for practice so much as to help with any 100% finished images that you're proud of and want brought through one final stage.  So, then you'd also want to make any real calls...

Sure, I appreciate that. I was thinking that some images would take to colour mastering better than others, which was implied by your post - and in that case, allowing you to pick the source image would give the most instructive result. I was hoping for an interesting contrast between "before" and "after" images, as much as anything.

My own favourites are "Missing" and "Radioactive Cats" which are both based on other artist's work; and "Sea Chase" which is largely monochromatic. All the images mentioned so far by both of us are also quite old, so I dunno now. :) Let me think about it some more... You never know, my next render might be my best one ever. :D