Bigs thanks to elnillo for his original design.
I wanted to start this weekend and so changed it a little bit to fit M3 nuts into it.
Printed on a Kossel Mini Delta with PETG from Extrudr.
Think3DPrint3D Kossel Mini
In Simplify3D use 6 top + 5 bottom layers and 1 outer pherimeter for maximum strength.
On my Kossel Mini I use 95 degree celcius for the bed, starting first layer with 235 degree following 220 for all other layers.
How to fit the nuts in
For fitting the nuts in use the carbon plate included with the S800 with washers (to save the carbon from beeing stressed) to the screws and then tighten them carefully until the nuts are flat to the surface. There should be some mechanical resistance at that point.