I think the upscaled is just for the webpage so you can choose whichever you prefer (I went with a 4x) for the download keep it 1x.
At least this is my understanding from reading various community posts.
You can use less than all 4
Adding a border helped a lot, thanks 👍 I had so many more tiles I could add a lot more details.
I used Pixel Studio on an Android tablet
I looked around and saw nobody mentioning this, I think it would be super cool to have the ability to subtract shapes from the ones in the scene to further customize stuff (would work wonders with primitives) .
I bet this is like a can of worms to implement :P