Lets just say that the default spacing can be considered "safe" when using the Center and Arrange.
It would be nice to have the distance parts are separated be configurable, to reduce travel and allow for denser plates without having to manipulate everything manually.
Secondly, it would be FANTASTIC to have the ability to specify the pattern, so instead of just a grid, you could choose circular, linear, or staggered like bricks.
This option would be especially useful if you could arrange parts by groupings, so that one set of small parts could be printed offset for example, not in a perfect grid.
Love S3D, thanks for the great work!