I have some ColorFab PeTG to try out as well. I will start with those settings. I have to find something I want to print though. LOL
The amethyst is nice. I was surprised in a good way. Another affordable PLA that is good.
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
It is hard to photograph the amethyst as it reflects so much. The piece has better detail than the gold even. Quite cool.
The flatness of it is a nice bonus you are right.