I work with images which are the highest determined possible resolution for target devices. For example, one of our target devices might be the newest or upcoming iPad. It will handle high resolution assets. But most of our target devices are mid-end. For those we scale down the atlases with Texture Packer.
Our producer is big on high resolution, so the assets I work with are big enough to make the Spine editor occasionally lag. For example, an image can be as large as 800800. Which at full scale for mobile devices is, I think, overkill. But some, the ones I try to make, might be really small. But not smaller than 44 px, because when downsized 4 times for lower-end devices the pixels will disappear.
When I think about it, I wouldn't want to work in Spine with actual image sizes. When I tried to do that when doing animation for a video, the computer and Spine lagged horrendously. Doesn't it lag for you?
And how well do small scales as 0.009 work out in these optimisation cases: say an image of a building is cut diagonally and rotated in Spine. They are placed so that the pixels are touching and not overlapping. If I scale down 0.009, might it start showing a tear in that spot? Well, probably one could simply overlap images... Example below:
