MakerBot Print is our newest print-prepration software, which supports native CAD files and STL assemblies,
allows you to interact with all your printers via the Cloud, and many other exciting new features.
I'm using a similar one: http://www.gearbest.com/3d-printer-parts/pp_591321.html
It sits about 5mm above the Nozzle, but some people have it closer because they have a Glas Plate in between.
I think adjustment between 0mm and 8mm or 10mm would be appropriate.