Printed on my UM2 in 0.1micron Infill: 0.2 Prints well in ABS or PLA. Please do not use a brim! It is very complicated to get that off the bottom part (accidentally printed it with one). As the adhesion surface of both parts is pretty big, you can probably print it without a raft as well. Post-Printing - Mount the parts together with spring-loaded screws I use M4 DIN 7380 half-round head screws with a 2.5mm hex and a length of 10mm. - Use rubber O-rings 3x1.5 or a few spring washers to get the necessary spring load and travel for the clip mechanism. Or alternatively print the stl with the integrated springs. - You don't need to tap the holes. Just use a little force until the screw grips into the plastic and then tighten them.