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.
Are you using PLA or PETG? I have found they don't work so well with PLA. PLA is too stiff, and looses its bite quickly, causing them to not stand out. PETG seems a little more slippery to me for assembly, but holds its bite longer. I also think the .3mm layer height adds deeper ridges, letting them lock together better. A brim could also make them harder to snap together, make sure to get all the brim completely off.
I print them with at .3mm layer height, with a .2mm initial layer. They also really don't need any infill.