This remix adds locking tabs to secure the top to the bottom, and to secure the bottom to the underside/backside of the hole. Also added a parameter to set the depth of the inside of the bottom part. I have not tested this yet! Please let me know if you have a problem.

The snaps are currently worthless--they snap off! Need redesigned.

The .zip file contains OpenSCAD library files you'll need. You can also get them from the source by searching Thingiverse.

If Thingiverse's Customizer is working, this is your best bet for customizing. If not,

• Install the Development version of OpenSCAD (http://www.openscad.org/downloads.html#snapshots)
• Enable the Customizer according to https://en.wikibooks.org/wiki/OpenSCAD_User_Manual/WIP#Customizer
• Open the .scad file
• Set your customizations
• Render
• Export as an STL file